A Hierarchical Multiscale Particle Computational Method for Simulation of Nanoscale Flows on 3D Unstructured Grids

DTIC Science & Technology

2009-08-14

3 is presented in Figure 12. These cases simulate the smallest na- nochannels with H = 0.1 /im and correspond to the near free -molecular flow with a...nal energy flux (or heat transfer rate) from a free stream with p, T.S to a flat plate with surface temperature T aligned with the flow is, 25 S2... Simulation of Nanoscale Flows on 3D Unstructured Grids 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9950-06-1-0236 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

Unstructured play for anxiety in pediatric inpatient care.

PubMed

Al-Yateem, Nabeel; Rossiter, Rachel C

2017-01-01

The purpose of this study was to examine the effects of unstructured play activities on the anxiety levels of hospitalized children. A nonequivalent control group pretest posttest design was employed for this study. The sample included children (N = 165) ages 4-7 years admitted to a large pediatric referral center in the United Arab Emirates. The control group (n = 84) received usual care, while the experimental group (n = 81) engaged in age-appropriate unstructured play activities using disposable games and toys. Parents and siblings, if present, were encouraged to participate. Research assistants conducted the play activities twice a day, with 30-min morning and evening sessions. Anxiety was measured at baseline and at the end of days 2 and 3 with a translated form of the Short-State-Trait Anxiety Inventory for Children. Anxiety scores in both groups were similar at baseline and decreased significantly over the 3 days. Compared with the control group, anxiety scores in the intervention group were significantly lower on day 2 (12.7 ± 2.3 vs. 10.7 ± 2.5, p = .003) and day 3 (10.6 ± 2.2 vs. 9.47 ± 2.4, p < .001). The greatest decrease occurred in the percentage of children in the experimental group with medium-level anxiety scores: baseline (n = 61, 75%), day 2 (n = 24, 30%), and day 3 (n = 0, 0%). This simple, low-cost play intervention implemented by nurses resulted in statistically and clinically significant decreases in the anxiety levels of children in an acute inpatient setting. © 2016, Wiley Periodicals, Inc.

P1 Nonconforming Finite Element Method for the Solution of Radiation Transport Problems

NASA Technical Reports Server (NTRS)

Kang, Kab S.

2002-01-01

The simulation of radiation transport in the optically thick flux-limited diffusion regime has been identified as one of the most time-consuming tasks within large simulation codes. Due to multimaterial complex geometry, the radiation transport system must often be solved on unstructured grids. In this paper, we investigate the behavior and the benefits of the unstructured P(sub 1) nonconforming finite element method, which has proven to be flexible and effective on related transport problems, in solving unsteady implicit nonlinear radiation diffusion problems using Newton and Picard linearization methods. Key words. nonconforrning finite elements, radiation transport, inexact Newton linearization, multigrid preconditioning

Parallel Higher-order Finite Element Method for Accurate Field Computations in Wakefield and PIC Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candel, A.; Kabel, A.; Lee, L.

Over the past years, SLAC's Advanced Computations Department (ACD), under SciDAC sponsorship, has developed a suite of 3D (2D) parallel higher-order finite element (FE) codes, T3P (T2P) and Pic3P (Pic2P), aimed at accurate, large-scale simulation of wakefields and particle-field interactions in radio-frequency (RF) cavities of complex shape. The codes are built on the FE infrastructure that supports SLAC's frequency domain codes, Omega3P and S3P, to utilize conformal tetrahedral (triangular)meshes, higher-order basis functions and quadratic geometry approximation. For time integration, they adopt an unconditionally stable implicit scheme. Pic3P (Pic2P) extends T3P (T2P) to treat charged-particle dynamics self-consistently using the PIC (particle-in-cell)more » approach, the first such implementation on a conformal, unstructured grid using Whitney basis functions. Examples from applications to the International Linear Collider (ILC), Positron Electron Project-II (PEP-II), Linac Coherent Light Source (LCLS) and other accelerators will be presented to compare the accuracy and computational efficiency of these codes versus their counterparts using structured grids.« less

WindTalker: A P2P-Based Low-Latency Anonymous Communication Network

NASA Astrophysics Data System (ADS)

Zhang, Jia; Duan, Haixin; Liu, Wu; Wu, Jianping

Compared with traditional static anonymous communication networks, the P2P architecture can provide higher anonymity in communication. However, the P2P architecture also leads to more challenges, such as route, stability, trust and so on. In this paper, we present WindTalker, a P2P-based low-latency anonymous communication network. It is a pure decentralized mix network and can provide low-latency services which help users hide their real identity in communication. In order to ensure stability and reliability, WindTalker imports “seed nodes” to help a peer join in the P2P network and the peer nodes can use gossip-based protocol to exchange active information. Moreover, WindTalker uses layer encryption to ensure the information of relayed messages cannot be leaked. In addition, malicious nodes in the network are the major threat to anonymity of P2P anonymous communication, so WindTalker imports a trust mechanism which can help the P2P network exclude malicious nodes and optimize the strategy of peer discovery, tunnel construction, and relaying etc. in anonymous communications. We deploy peer nodes of WindTalker in our campus network to test reliability and analyze anonymity in theory. The network measurement and simulation analysis shows that WindTalker can provide low-latency and reliable anonymous communication services.

A distributed incentive compatible pricing mechanism for P2P networks

NASA Astrophysics Data System (ADS)

Zhang, Jie; Zhao, Zheng; Xiong, Xiao; Shi, Qingwei

2007-09-01

Peer-to-Peer (P2P) systems are currently receiving considerable interest. However, as experience with P2P networks shows, the selfish behaviors of peers may lead to serious problems of P2P network, such as free-riding and white-washing. In order to solve these problems, there are increasing considerations on reputation system design in the study of P2P networks. Most of the existing works is concerning probabilistic estimation or social networks to evaluate the trustworthiness for a peer to others. However, these models can not be efficient all the time. In this paper, our aim is to provide a general mechanism that can maximize P2P networks social welfare in a way of Vickrey-Clarke-Groves family, while assuming every peer in P2P networks is rational and selfish, which means they only concern about their own outcome. This mechanism has some desirable properties using an O(n) algorithm: (1) incentive compatibility, every peer truly report its connection type; (2) individually rationality; and (3) fully decentralized, we design a multiple-principal multiple-agent model, concerning about the service provider and service requester individually.

Impact of Machine-Translated Text on Entity and Relationship Extraction

DTIC Science & Technology

2014-12-01

20 1 1. Introduction Using social network analysis tools is an important asset in...semantic modeling software to automatically build detailed network models from unstructured text. Contour imports unstructured text and then maps the text...onto an existing ontology of frames at the sentence level, using FrameNet, a structured language model, and through Semantic Role Labeling ( SRL

SKILLED BIMANUAL TRAINING DRIVES MOTOR CORTEX PLASTICITY IN CHILDREN WITH UNILATERAL CEREBRAL PALSY

PubMed Central

Friel, Kathleen M.; Kuo, Hsing-Ching; Fuller, Jason; Ferre, Claudio L.; Brandão, Marina; Carmel, Jason B.; Bleyenheuft, Yannick; Gowatsky, Jaimie L.; Stanford, Arielle D.; Rowny, Stefan B.; Luber, Bruce; Bassi, Bruce; Murphy, David LK; Lisanby, Sarah H.; Gordon, Andrew M.

2015-01-01

Background Intensive bimanual therapy can improve hand function in children with unilateral spastic cerebral palsy (USCP). We compared the effects of structured bimanual skill training vs. unstructured bimanual practice on motor outcomes and motor map plasticity in children with USCP. Objective We hypothesized that structured skill training would produce greater motor map plasticity than unstructured practice. Methods Twenty children with USCP (average age 9,5; 12 males) received therapy in a day-camp-setting, 6 h/day, 5 days/week, for 3 weeks. In structured skill training (n=10), children performed progressively more difficult movements and practiced functional goals. In unstructured practice (n=10), children engaged in bimanual activities but did not practice skillful movements or functional goals. We used the Assisting Hand Assessment (AHA), Jebsen-Taylor test of Hand Function (JTTHF) and Canadian Occupational Performance Measure (COPM) to measure hand function. We used single-pulse transcranial magnetic stimulation (TMS) to map the representation of first dorsal interosseous (FDI) and flexor carpi radialis (FCR) muscles bilaterally. Results Both groups showed significant improvements in bimanual hand use (AHA; p<0.05) and hand dexterity (JTTHF; p<0.001). However, only the structured skill group showed increases in the size of the affected hand motor map and amplitudes of motor evoked potentials (p<0.01). Most children who showed the most functional improvements (COPM) had the largest changes in map size. Conclusions These findings uncover a dichotomy of plasticity: the unstructured practice group improved hand function but did not show changes in motor maps. Skill training is important for driving motor cortex plasticity in children with USCP. PMID:26867559

Performance Evaluation of Peer-to-Peer Progressive Download in Broadband Access Networks

NASA Astrophysics Data System (ADS)

Shibuya, Megumi; Ogishi, Tomohiko; Yamamoto, Shu

P2P (Peer-to-Peer) file sharing architectures have scalable and cost-effective features. Hence, the application of P2P architectures to media streaming is attractive and expected to be an alternative to the current video streaming using IP multicast or content delivery systems because the current systems require expensive network infrastructures and large scale centralized cache storage systems. In this paper, we investigate the P2P progressive download enabling Internet video streaming services. We demonstrated the capability of the P2P progressive download in both laboratory test network as well as in the Internet. Through the experiments, we clarified the contribution of the FTTH links to the P2P progressive download in the heterogeneous access networks consisting of FTTH and ADSL links. We analyzed the cause of some download performance degradation occurred in the experiment and discussed about the effective methods to provide the video streaming service using P2P progressive download in the current heterogeneous networks.

Fuzzy-rule-based Adaptive Resource Control for Information Sharing in P2P Networks

NASA Astrophysics Data System (ADS)

Wu, Zhengping; Wu, Hao

With more and more peer-to-peer (P2P) technologies available for online collaboration and information sharing, people can launch more and more collaborative work in online social networks with friends, colleagues, and even strangers. Without face-to-face interactions, the question of who can be trusted and then share information with becomes a big concern of a user in these online social networks. This paper introduces an adaptive control service using fuzzy logic in preference definition for P2P information sharing control, and designs a novel decision-making mechanism using formal fuzzy rules and reasoning mechanisms adjusting P2P information sharing status following individual users' preferences. Applications of this adaptive control service into different information sharing environments show that this service can provide a convenient and accurate P2P information sharing control for individual users in P2P networks.

Correlates of moderate-to-vigorous physical activity among preschoolers during unstructured outdoor play periods.

PubMed

Nicaise, Virginie; Kahan, David; Sallis, James F

2011-10-01

Quantify moderate-to-vigorous physical activity (MVPA) and its correlates in preschool children during outdoor unstructured play periods using direct observation. Cross-sectional data consisting of 204 observation periods collected from 51 four- and five-year-old children using the Observation System for Recording Physical Activity in Children - Preschool (OSRAC-P) at a preschool in southern California, autumn and spring 2009-2010. Gender and BMI classification and OSRAC-P environmental codes were related to observed MVPA in multiple logistic regression models. Less than 21% of intervals were spent in MVPA overall. Boys and normal weight children engaged in higher intensity levels than their respective counterparts. More MVPA was associated with normal weight (OR=2.49-3.25, R(2)=3%), location (grass, playground, looping cycle path; OR=3.21-4.90, R(2)=4-12%), play context (ball/objects, wheel, open space; OR=2.78-8.51, R(2)=9%), and group composition (solitary, one-on-one; OR=1.34-2.08, R(2)=1%). Open spaces located in playgrounds and grass fields, and activity-genic portable equipment, manipulative objects, and riding vehicles are some design and equipment features that appear to foster MVPA. Lowering play space density and engaging children through teacher prompts and teacher-arranged activities may further increase MVPA on playgrounds. Copyright © 2011 Elsevier Inc. All rights reserved.

Towards the Engineering of Dependable P2P-Based Network Control — The Case of Timely Routing Control Messages

NASA Astrophysics Data System (ADS)

Tutschku, Kurt; Nakao, Akihiro

This paper introduces a methodology for engineering best-effort P2P algorithms into dependable P2P-based network control mechanism. The proposed method is built upon an iterative approach consisting of improving the original P2P algorithm by appropriate mechanisms and of thorough performance assessment with respect to dependability measures. The potential of the methodology is outlined by the example of timely routing control for vertical handover in B3G wireless networks. In detail, the well-known Pastry and CAN algorithms are enhanced to include locality. By showing how to combine algorithmic enhancements with performance indicators, this case study paves the way for future engineering of dependable network control mechanisms through P2P algorithms.

Feedback modulation of neural network synchrony and seizure susceptibility by Mdm2-p53-Nedd4-2 signaling.

PubMed

Jewett, Kathryn A; Christian, Catherine A; Bacos, Jonathan T; Lee, Kwan Young; Zhu, Jiuhe; Tsai, Nien-Pei

2016-03-22

Neural network synchrony is a critical factor in regulating information transmission through the nervous system. Improperly regulated neural network synchrony is implicated in pathophysiological conditions such as epilepsy. Despite the awareness of its importance, the molecular signaling underlying the regulation of neural network synchrony, especially after stimulation, remains largely unknown. In this study, we show that elevation of neuronal activity by the GABA(A) receptor antagonist, Picrotoxin, increases neural network synchrony in primary mouse cortical neuron cultures. The elevation of neuronal activity triggers Mdm2-dependent degradation of the tumor suppressor p53. We show here that blocking the degradation of p53 further enhances Picrotoxin-induced neural network synchrony, while promoting the inhibition of p53 with a p53 inhibitor reduces Picrotoxin-induced neural network synchrony. These data suggest that Mdm2-p53 signaling mediates a feedback mechanism to fine-tune neural network synchrony after activity stimulation. Furthermore, genetically reducing the expression of a direct target gene of p53, Nedd4-2, elevates neural network synchrony basally and occludes the effect of Picrotoxin. Finally, using a kainic acid-induced seizure model in mice, we show that alterations of Mdm2-p53-Nedd4-2 signaling affect seizure susceptibility. Together, our findings elucidate a critical role of Mdm2-p53-Nedd4-2 signaling underlying the regulation of neural network synchrony and seizure susceptibility and reveal potential therapeutic targets for hyperexcitability-associated neurological disorders.

A suffix arrays based approach to semantic search in P2P systems

NASA Astrophysics Data System (ADS)

Shi, Qingwei; Zhao, Zheng; Bao, Hu

2007-09-01

Building a semantic search system on top of peer-to-peer (P2P) networks is becoming an attractive and promising alternative scheme for the reason of scalability, Data freshness and search cost. In this paper, we present a Suffix Arrays based algorithm for Semantic Search (SASS) in P2P systems, which generates a distributed Semantic Overlay Network (SONs) construction for full-text search in P2P networks. For each node through the P2P network, SASS distributes document indices based on a set of suffix arrays, by which clusters are created depending on words or phrases shared between documents, therefore, the search cost for a given query is decreased by only scanning semantically related documents. In contrast to recently announced SONs scheme designed by using metadata or predefined-class, SASS is an unsupervised approach for decentralized generation of SONs. SASS is also an incremental, linear time algorithm, which efficiently handle the problem of nodes update in P2P networks. Our simulation results demonstrate that SASS yields high search efficiency in dynamic environments.

A finite-volume module for all-scale Earth-system modelling at ECMWF

NASA Astrophysics Data System (ADS)

Kühnlein, Christian; Malardel, Sylvie; Smolarkiewicz, Piotr

2017-04-01

We highlight recent advancements in the development of the finite-volume module (FVM) (Smolarkiewicz et al., 2016) for the IFS at ECMWF. FVM represents an alternative dynamical core that complements the operational spectral dynamical core of the IFS with new capabilities. Most notably, these include a compact-stencil finite-volume discretisation, flexible meshes, conservative non-oscillatory transport and all-scale governing equations. As a default, FVM solves the compressible Euler equations in a geospherical framework (Szmelter and Smolarkiewicz, 2010). The formulation incorporates a generalised terrain-following vertical coordinate. A hybrid computational mesh, fully unstructured in the horizontal and structured in the vertical, enables efficient global atmospheric modelling. Moreover, a centred two-time-level semi-implicit integration scheme is employed with 3D implicit treatment of acoustic, buoyant, and rotational modes. The associated 3D elliptic Helmholtz problem is solved using a preconditioned Generalised Conjugate Residual approach. The solution procedure employs the non-oscillatory finite-volume MPDATA advection scheme that is bespoke for the compressible dynamics on the hybrid mesh (Kühnlein and Smolarkiewicz, 2017). The recent progress of FVM is illustrated with results of benchmark simulations of intermediate complexity, and comparison to the operational spectral dynamical core of the IFS. C. Kühnlein, P.K. Smolarkiewicz: An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics, J. Comput. Phys. (2017), in press. P.K. Smolarkiewicz, W. Deconinck, M. Hamrud, C. Kühnlein, G. Mozdzynski, J. Szmelter, N.P. Wedi: A finite-volume module for simulating global all-scale atmospheric flows, J. Comput. Phys. 314 (2016) 287-304. J. Szmelter, P.K. Smolarkiewicz: An edge-based unstructured mesh discretisation in geospherical framework, J. Comput. Phys. 229 (2010) 4980-4995.

Mutation of CD2AP and SH3KBP1 Binding Motif in Alphavirus nsP3 Hypervariable Domain Results in Attenuated Virus.

PubMed

Mutso, Margit; Morro, Ainhoa Moliner; Smedberg, Cecilia; Kasvandik, Sergo; Aquilimeba, Muriel; Teppor, Mona; Tarve, Liisi; Lulla, Aleksei; Lulla, Valeria; Saul, Sirle; Thaa, Bastian; McInerney, Gerald M; Merits, Andres; Varjak, Margus

2018-04-27

Infection by Chikungunya virus (CHIKV) of the Old World alphaviruses (family Togaviridae) in humans can cause arthritis and arthralgia. The virus encodes four non-structural proteins (nsP) (nsP1, nsp2, nsP3 and nsP4) that act as subunits of the virus replicase. These proteins also interact with numerous host proteins and some crucial interactions are mediated by the unstructured C-terminal hypervariable domain (HVD) of nsP3. In this study, a human cell line expressing EGFP tagged with CHIKV nsP3 HVD was established. Using quantitative proteomics, it was found that CHIKV nsP3 HVD can bind cytoskeletal proteins, including CD2AP, SH3KBP1, CAPZA1, CAPZA2 and CAPZB. The interaction with CD2AP was found to be most evident; its binding site was mapped to the second SH3 ligand-like element in nsP3 HVD. Further assessment indicated that CD2AP can bind to nsP3 HVDs of many different New and Old World alphaviruses. Mutation of the short binding element hampered the ability of the virus to establish infection. The mutation also abolished ability of CD2AP to co-localise with nsP3 and replication complexes of CHIKV; the same was observed for Semliki Forest virus (SFV) harbouring a similar mutation. Similar to CD2AP, its homolog SH3KBP1 also bound the identified motif in CHIKV and SFV nsP3.

Child, family and environmental correlates of children's motor skill proficiency.

PubMed

Barnett, Lisa; Hinkley, Trina; Okely, Anthony D; Salmon, Jo

2013-07-01

To identify factors associated with children's motor skills. Cross-sectional. Australian preschool-aged children were recruited in 2009 as part of a larger study. Parent proxy-report of child factors (age, sex, parent perception of child skill, participation in unstructured and structured activity), self-report of parent factors (confidence in their own skills to support child's activity, parent-child physical activity interaction, parent physical activity) and perceived environmental factors (play space visits, equipment at home) were collected. Moderate to vigorous physical activity (MVPA) (ActiGraph GT1M accelerometer) and motor skills (Test of Gross Motor Development-2) were also assessed. After age adjustment, variables were checked for association with raw object control and locomotor scores. Variables with associations of p<0.20 were entered into two multiple regression models with locomotor/object control as respective outcome variables. Motor skills were assessed for 76 children (42 female), mean [SD] age=4.1 [0.68]; 71 completed parent proxy-report and 53 had valid MVPA data. Child age, swimming lessons, and home equipment were positively associated explaining 20% of locomotor skill variance, but only age was significant (β=0.36, p=0.002). Child age and sex, unstructured activity participation, MVPA%, parent confidence, home equipment (all positively associated), and dance participation (inversely associated) explained 32% object control variance. But only age (β=0.67, p<0.0001), MVPA% (β=0.37, p=0.038) and no dance (β=-0.34, p=0.028) were significant. Motor skill correlates differ according to skill category and are context specific with child level correlates appearing more important. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Gas-liquid interface-mediated room-temperature synthesis of "clean" PdNiP alloy nanoparticle networks with high catalytic activity for ethanol oxidation.

PubMed

Wang, Rongfang; Ma, Yuanyuan; Wang, Hui; Key, Julian; Ji, Shan

2014-11-04

PdNiP alloy nanoparticle networks (PdNiP NN) were prepared by simultaneous reduction of PdCl2, NiCl2 and NaH2PO2 with NaBH4via a gas-liquid interface reaction at room temperature using N2 bubbles. PdNiP NN had markedly higher activity and durability for ethanol oxidation than PdNi nanoparticle networks and PdNiP grain aggregates.

An Adaptive Failure Detector Based on Quality of Service in Peer-to-Peer Networks

PubMed Central

Dong, Jian; Ren, Xiao; Zuo, Decheng; Liu, Hongwei

2014-01-01

The failure detector is one of the fundamental components that maintain high availability of Peer-to-Peer (P2P) networks. Under different network conditions, the adaptive failure detector based on quality of service (QoS) can achieve the detection time and accuracy required by upper applications with lower detection overhead. In P2P systems, complexity of network and high churn lead to high message loss rate. To reduce the impact on detection accuracy, baseline detection strategy based on retransmission mechanism has been employed widely in many P2P applications; however, Chen's classic adaptive model cannot describe this kind of detection strategy. In order to provide an efficient service of failure detection in P2P systems, this paper establishes a novel QoS evaluation model for the baseline detection strategy. The relationship between the detection period and the QoS is discussed and on this basis, an adaptive failure detector (B-AFD) is proposed, which can meet the quantitative QoS metrics under changing network environment. Meanwhile, it is observed from the experimental analysis that B-AFD achieves better detection accuracy and time with lower detection overhead compared to the traditional baseline strategy and the adaptive detectors based on Chen's model. Moreover, B-AFD has better adaptability to P2P network. PMID:25198005

Efficient File Sharing by Multicast - P2P Protocol Using Network Coding and Rank Based Peer Selection

NASA Technical Reports Server (NTRS)

Stoenescu, Tudor M.; Woo, Simon S.

2009-01-01

In this work, we consider information dissemination and sharing in a distributed peer-to-peer (P2P highly dynamic communication network. In particular, we explore a network coding technique for transmission and a rank based peer selection method for network formation. The combined approach has been shown to improve information sharing and delivery to all users when considering the challenges imposed by the space network environments.

Hierarchical Data Distribution Scheme for Peer-to-Peer Networks

NASA Astrophysics Data System (ADS)

Bhushan, Shashi; Dave, M.; Patel, R. B.

2010-11-01

In the past few years, peer-to-peer (P2P) networks have become an extremely popular mechanism for large-scale content sharing. P2P systems have focused on specific application domains (e.g. music files, video files) or on providing file system like capabilities. P2P is a powerful paradigm, which provides a large-scale and cost-effective mechanism for data sharing. P2P system may be used for storing data globally. Can we implement a conventional database on P2P system? But successful implementation of conventional databases on the P2P systems is yet to be reported. In this paper we have presented the mathematical model for the replication of the partitions and presented a hierarchical based data distribution scheme for the P2P networks. We have also analyzed the resource utilization and throughput of the P2P system with respect to the availability, when a conventional database is implemented over the P2P system with variable query rate. Simulation results show that database partitions placed on the peers with higher availability factor perform better. Degradation index, throughput, resource utilization are the parameters evaluated with respect to the availability factor.

Integrating XQuery-Enabled SCORM XML Metadata Repositories into an RDF-Based E-Learning P2P Network

ERIC Educational Resources Information Center

Qu, Changtao; Nejdl, Wolfgang

2004-01-01

Edutella is an RDF-based E-Learning P2P network that is aimed to accommodate heterogeneous learning resource metadata repositories in a P2P manner and further facilitate the exchange of metadata between these repositories based on RDF. Whereas Edutella provides RDF metadata repositories with a quite natural integration approach, XML metadata…

Reliable file sharing in distributed operating system using web RTC

NASA Astrophysics Data System (ADS)

Dukiya, Rajesh

2017-12-01

Since, the evolution of distributed operating system, distributed file system is come out to be important part in operating system. P2P is a reliable way in Distributed Operating System for file sharing. It was introduced in 1999, later it became a high research interest topic. Peer to Peer network is a type of network, where peers share network workload and other load related tasks. A P2P network can be a period of time connection, where a bunch of computers connected by a USB (Universal Serial Bus) port to transfer or enable disk sharing i.e. file sharing. Currently P2P requires special network that should be designed in P2P way. Nowadays, there is a big influence of browsers in our life. In this project we are going to study of file sharing mechanism in distributed operating system in web browsers, where we will try to find performance bottlenecks which our research will going to be an improvement in file sharing by performance and scalability in distributed file systems. Additionally, we will discuss the scope of Web Torrent file sharing and free-riding in peer to peer networks.

SAR405838: An optimized inhibitor of MDM2-p53 interaction that induces complete and durable tumor regression

DOE PAGES

Wang, Shaomeng; Sun, Wei; Zhao, Yujun; ...

2014-08-21

Blocking the MDM2-p53 protein-protein interaction has long been considered to offer a broad cancer therapeutic strategy, despite the potential risks of selecting tumors harboring p53 mutations that escape MDM2 control. In this study, we report a novel small molecule inhibitor of the MDM2-p53 interaction, SAR405838 (MI-77301) that has been advanced into Phase I clinical trials. SAR405838 binds to MDM2 with K i = 0.88 nM and has high specificity over other proteins. A co-crystal structure of the SAR405838:MDM2 complex shows that in addition to mimicking three key p53 amino acid residues, the inhibitor captures additional interactions not observed in themore » p53-MDM2 complex and induces refolding of the short, unstructured MDM2 N-terminal region to achieve its high affinity. SAR405838 effectively activates wild-type p53 in vitro and in xenograft tumor tissue of leukemia and solid tumors, leading to p53-dependent cell cycle arrest and/or apoptosis. At well-tolerated dose schedules, SAR405838 achieves either durable tumor regression or complete tumor growth inhibition in mouse xenograft models of SJSA-1 osteosarcoma, RS4;11 acute leukemia, LNCaP prostate cancer and HCT-116 colon cancer. Remarkably, a single oral dose of SAR405838 is sufficient to achieve complete tumor regression in the SJSA-1 model. Mechanistically, robust transcriptional up-regulation of PUMA induced by SAR405838 results in strong apoptosis in tumor tissue, leading to complete tumor regression. Lastly, our findings provide a preclinical basis upon which to evaluate SAR405838 as a therapeutic agent in patients whose tumors retain wild-type p53.« less

Wakefield Computations for the CLIC PETS using the Parallel Finite Element Time-Domain Code T3P

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candel, A; Kabel, A.; Lee, L.

In recent years, SLAC's Advanced Computations Department (ACD) has developed the high-performance parallel 3D electromagnetic time-domain code, T3P, for simulations of wakefields and transients in complex accelerator structures. T3P is based on advanced higher-order Finite Element methods on unstructured grids with quadratic surface approximation. Optimized for large-scale parallel processing on leadership supercomputing facilities, T3P allows simulations of realistic 3D structures with unprecedented accuracy, aiding the design of the next generation of accelerator facilities. Applications to the Compact Linear Collider (CLIC) Power Extraction and Transfer Structure (PETS) are presented.

Effect of pH on the rheological and structural properties of gels of water-washed chicken-breast muscle at physiological ionic strength.

PubMed

Feng, Y; Hultin, H O

2001-08-01

Adjustment of pH from 6.4 to neutrality improved gelling ability and water-holding capacity of twice water-washed, minced chicken-breast muscle significantly at physiological ionic strength, at which the majority of the myofibrillar proteins, including myosin, are not soluble. A strain value of 2.2 was obtained at neutral pH. Myofibrils were the main components of the gel network at both pH 6.4 and 7.0; however, the myofibrillar distribution varied with the pH value. At pH 6.4, myofibrils formed a network of localized aggregates leaving large voids between, whereas at neutral pH, an evenly distributed network of myofibrils was formed. In addition, at neutral pH, a network of fine strands was found within the network of myofibrils. The network was much less developed at pH 6.4. The thin and thick filaments within each myofibrillar structure were disorganized at both pH values. The intramyofibrillar spaces were larger at neutral pH than at pH 6.4. It was proposed that adjustment of pH to neutrality increased electrostatic repulsion leading to a more even distribution of the myofibrillar proteins, a key factor responsible for the improved gel strength and water-holding capacity.

A Spectral Element Discretisation on Unstructured Triangle / Tetrahedral Meshes for Elastodynamics

NASA Astrophysics Data System (ADS)

May, Dave A.; Gabriel, Alice-A.

2017-04-01

The spectral element method (SEM) defined over quadrilateral and hexahedral element geometries has proven to be a fast, accurate and scalable approach to study wave propagation phenomena. In the context of regional scale seismology and or simulations incorporating finite earthquake sources, the geometric restrictions associated with hexahedral elements can limit the applicability of the classical quad./hex. SEM. Here we describe a continuous Galerkin spectral element discretisation defined over unstructured meshes composed of triangles (2D), or tetrahedra (3D). The method uses a stable, nodal basis constructed from PKD polynomials and thus retains the spectral accuracy and low dispersive properties of the classical SEM, in addition to the geometric versatility provided by unstructured simplex meshes. For the particular basis and quadrature rule we have adopted, the discretisation results in a mass matrix which is not diagonal, thereby mandating linear solvers be utilised. To that end, we have developed efficient solvers and preconditioners which are robust with respect to the polynomial order (p), and possess high arithmetic intensity. Furthermore, we also consider using implicit time integrators, together with a p-multigrid preconditioner to circumvent the CFL condition. Implicit time integrators become particularly relevant when considering solving problems on poor quality meshes, or meshes containing elements with a widely varying range of length scales - both of which frequently arise when meshing non-trivial geometries. We demonstrate the applicability of the new method by examining a number of two- and three-dimensional wave propagation scenarios. These scenarios serve to characterise the accuracy and cost of the new method. Lastly, we will assess the potential benefits of using implicit time integrators for regional scale wave propagation simulations.

Volatile release from self-assembly structured emulsions: effect of monoglyceride content, oil content, and oil type.

PubMed

Mao, Like; Roos, Yrjö H; Miao, Song

2013-02-20

Monoglycerides (MGs) can form self-assembled structures in emulsions, which can be used to control volatile release. In this study, initial headspace concentrations (C(initial)), maximum headspace concentrations (C(max)), release rates, and partition coefficients of propanol, diacetyl, hexanal, and limonene were determined in MG structured oil-in-water emulsions using dynamic and static headspace analyses. For all of the volatile compounds, C(initial) values above structured emulsions were significantly lower than those above unstructured emulsions and decreased with increasing MG contents (p < 0.05). However, volatiles had higher release rates in emulsions with higher MG contents. When oil content was reduced from 20 to 10%, C(initial) and C(max) increased for limonene and hexanal and decreased for propanol and diacetyl. When different oils were applied, both C(initial) and C(max) were significantly lower in medium-chain triglyceride emulsions than in soybean oil emulsions (p < 0.05). Static headspace analysis revealed that volatile compounds had significantly lower air-emulsion partition coefficients in the structured emulsions than in unstructured emulsions (p < 0.05). These results indicated that MG structured emulsions can be potentially used as delivery systems to modulate volatile release.

Strategies for P2P connectivity in reconfigurable converged wired/wireless access networks.

PubMed

Puerto, Gustavo; Mora, José; Ortega, Beatriz; Capmany, José

2010-12-06

This paper presents different strategies to define the architecture of a Radio-Over-Fiber (RoF) Access networks enabling Peer-to-Peer (P2P) functionalities. The architectures fully exploit the flexibility of a wavelength router based on the feedback configuration of an Arrayed Waveguide Grating (AWG) and an optical switch to broadcast P2P services among diverse infrastructures featuring dynamic channel allocation and enabling an optical platform for 3G and beyond wireless backhaul requirements. The first architecture incorporates a tunable laser to generate a dedicated wavelength for P2P purposes and the second architecture takes advantage of reused wavelengths to enable the P2P connectivity among Optical Network Units (ONUs) or Base Stations (BS). While these two approaches allow the P2P connectivity in a one at a time basis (1:1), the third architecture enables the broadcasting of P2P sessions among different ONUs or BSs at the same time (1:M). Experimental assessment of the proposed architecture shows approximately 0.6% Error Vector Magnitude (EVM) degradation for wireless services and 1 dB penalty in average for 1 x 10(-12) Bit Error Rate (BER) for wired baseband services.

Security Issues in Cross-Organizational Peer-to-Peer Applications and Some Solutions

NASA Astrophysics Data System (ADS)

Gupta, Ankur; Awasthi, Lalit K.

Peer-to-Peer networks have been widely used for sharing millions of terabytes of content, for large-scale distributed computing and for a variety of other novel applications, due to their scalability and fault-tolerance. However, the scope of P2P networks has somehow been limited to individual computers connected to the internet. P2P networks are also notorious for blatant copyright violations and facilitating several kinds of security attacks. Businesses and large organizations have thus stayed away from deploying P2P applications citing security loopholes in P2P systems as the biggest reason for non-adoption. In theory P2P applications can help fulfill many organizational requirements such as collaboration and joint projects with other organizations, access to specialized computing infrastructure and finally accessing the specialized information/content and expert human knowledge available at other organizations. These potentially beneficial interactions necessitate that the research community attempt to alleviate the security shortcomings in P2P systems and ensure their acceptance and wide deployment. This research paper therefore examines the security issues prevalent in enabling cross-organizational P2P interactions and provides some technical insights into how some of these issues can be resolved.

Measurement and Statistics of Application Business in Complex Internet

NASA Astrophysics Data System (ADS)

Wang, Lei; Li, Yang; Li, Yipeng; Wu, Shuhang; Song, Shiji; Ren, Yong

Owing to independent topologies and autonomic routing mechanism, the logical networks formed by Internet application business behavior cause the significant influence on the physical networks. In this paper, the backbone traffic of TUNET (Tsinghua University Networks) is measured, further more, the two most important application business: HTTP and P2P are analyzed at IP-packet level. It is shown that uplink HTTP and P2P packets behavior presents spatio-temporal power-law characteristics with exponents 1.25 and 1.53 respectively. Downlink HTTP packets behavior also presents power-law characteristics, but has more little exponents γ = 0.82 which differs from traditional complex networks research result. Moreover, downlink P2P packets distribution presents an approximate power-law which means that flow equilibrium profits little from distributed peer-to peer mechanism actually.

Collaborative human-machine analysis to disambiguate entities in unstructured text and structured datasets

NASA Astrophysics Data System (ADS)

Davenport, Jack H.

2016-05-01

Intelligence analysts demand rapid information fusion capabilities to develop and maintain accurate situational awareness and understanding of dynamic enemy threats in asymmetric military operations. The ability to extract relationships between people, groups, and locations from a variety of text datasets is critical to proactive decision making. The derived network of entities must be automatically created and presented to analysts to assist in decision making. DECISIVE ANALYTICS Corporation (DAC) provides capabilities to automatically extract entities, relationships between entities, semantic concepts about entities, and network models of entities from text and multi-source datasets. DAC's Natural Language Processing (NLP) Entity Analytics model entities as complex systems of attributes and interrelationships which are extracted from unstructured text via NLP algorithms. The extracted entities are automatically disambiguated via machine learning algorithms, and resolution recommendations are presented to the analyst for validation; the analyst's expertise is leveraged in this hybrid human/computer collaborative model. Military capability is enhanced by these NLP Entity Analytics because analysts can now create/update an entity profile with intelligence automatically extracted from unstructured text, thereby fusing entity knowledge from structured and unstructured data sources. Operational and sustainment costs are reduced since analysts do not have to manually tag and resolve entities.

New insights into flavivirus biology: the influence of pH over interactions between prM and E proteins

NASA Astrophysics Data System (ADS)

Oliveira, Edson R. A.; de Alencastro, Ricardo B.; Horta, Bruno A. C.

2017-11-01

Diseases caused by flaviviruses, such as dengue and zika, are globally recognized as major threats. During infection, a critical point in their replicative cycle is the maturation step, which occurs throughout the cellular exocytic pathway. This step is a pH-dependent process that involves the modification of the viral envelope by converting prM (pre-membrane) into M (membrane) proteins with the release of a "pr peptide". After this reaction, the pr peptides remain bound to the viral envelope while the virions cross the acidic trans-Golgi network, and are released only at neutral pH after secretion of the virus particles. Despite this current knowledge, the molecular basis of the flavivirus maturation step is largely unknown. Here, based on the crystal structure of the dengue pr-E complex ("pr peptide" bound to virus envelope protein) and using molecular dynamics simulations, we found that the pH shift from acidic to neutral yields considerable structural changes in the system. Dynamic cross correlation maps and root mean square deviation analyses revealed that the pr-E junction is clearly unstable under neutral pH. Secondary structure analysis also revealed that the fusion loop region, present in the E protein, is sensitive to pH and tends to unstructure at a neutral environment. Moreover, we found that five residues present in the E protein, Gly102, His244, Thr70, Thr68 and Asn67 are critical to confer stability to the pr-E complex while inside the Golgi apparatus. This work brings details about the dynamical behavior of the pr-E system, helps to better understand the flavivirus biology and may also be of use in the development of novel antiviral strategies.

Motion planning for autonomous vehicle based on radial basis function neural network in unstructured environment.

PubMed

Chen, Jiajia; Zhao, Pan; Liang, Huawei; Mei, Tao

2014-09-18

The autonomous vehicle is an automated system equipped with features like environment perception, decision-making, motion planning, and control and execution technology. Navigating in an unstructured and complex environment is a huge challenge for autonomous vehicles, due to the irregular shape of road, the requirement of real-time planning, and the nonholonomic constraints of vehicle. This paper presents a motion planning method, based on the Radial Basis Function (RBF) neural network, to guide the autonomous vehicle in unstructured environments. The proposed algorithm extracts the drivable region from the perception grid map based on the global path, which is available in the road network. The sample points are randomly selected in the drivable region, and a gradient descent method is used to train the RBF network. The parameters of the motion-planning algorithm are verified through the simulation and experiment. It is observed that the proposed approach produces a flexible, smooth, and safe path that can fit any road shape. The method is implemented on autonomous vehicle and verified against many outdoor scenes; furthermore, a comparison of proposed method with the existing well-known Rapidly-exploring Random Tree (RRT) method is presented. The experimental results show that the proposed method is highly effective in planning the vehicle path and offers better motion quality.

Motion Planning for Autonomous Vehicle Based on Radial Basis Function Neural Network in Unstructured Environment

PubMed Central

Chen, Jiajia; Zhao, Pan; Liang, Huawei; Mei, Tao

2014-01-01

The autonomous vehicle is an automated system equipped with features like environment perception, decision-making, motion planning, and control and execution technology. Navigating in an unstructured and complex environment is a huge challenge for autonomous vehicles, due to the irregular shape of road, the requirement of real-time planning, and the nonholonomic constraints of vehicle. This paper presents a motion planning method, based on the Radial Basis Function (RBF) neural network, to guide the autonomous vehicle in unstructured environments. The proposed algorithm extracts the drivable region from the perception grid map based on the global path, which is available in the road network. The sample points are randomly selected in the drivable region, and a gradient descent method is used to train the RBF network. The parameters of the motion-planning algorithm are verified through the simulation and experiment. It is observed that the proposed approach produces a flexible, smooth, and safe path that can fit any road shape. The method is implemented on autonomous vehicle and verified against many outdoor scenes; furthermore, a comparison of proposed method with the existing well-known Rapidly-exploring Random Tree (RRT) method is presented. The experimental results show that the proposed method is highly effective in planning the vehicle path and offers better motion quality. PMID:25237902

P2MP MPLS-Based Hierarchical Service Management System

NASA Astrophysics Data System (ADS)

Kumaki, Kenji; Nakagawa, Ikuo; Nagami, Kenichi; Ogishi, Tomohiko; Ano, Shigehiro

This paper proposes a point-to-multipoint (P2MP) Multi-Protocol Label Switching (MPLS) based hierarchical service management system. Traditionally, general management systems deployed in some service providers control MPLS Label Switched Paths (LSPs) (e.g., RSVP-TE and LDP) and services (e.g., L2VPN, L3VPN and IP) separately. In order for dedicated management systems for MPLS LSPs and services to cooperate with each other automatically, a hierarchical service management system has been proposed with the main focus on point-to-point (P2P) TE LSPs in MPLS path management. In the case where P2MP TE LSPs and services are deployed in MPLS networks, the dedicated management systems for P2MP TE LSPs and services must work together automatically. Therefore, this paper proposes a new algorithm that uses a correlation between P2MP TE LSPs and multicast VPN services based on a P2MP MPLS-based hierarchical service management architecture. Also, the capacity and performance of the proposed algorithm are evaluated by simulations, which are actually based on certain real MPLS production networks, and are compared to that of the algorithm for P2P TE LSPs. Results show this system is very scalable within real MPLS production networks. This system, with the automatic correlation, appears to be deployable in real MPLS production networks.

The UGRID Reader - A ParaView Plugin for the Visualization of Unstructured Climate Model Data in NetCDF Format

NASA Astrophysics Data System (ADS)

Brisc, Felicia; Vater, Stefan; Behrens, Joern

2016-04-01

We present the UGRID Reader, a visualization software component that implements the UGRID Conventions into Paraview. It currently supports the reading and visualization of 2D unstructured triangular, quadrilateral and mixed triangle/quadrilateral meshes, while the data can be defined per cell or per vertex. The Climate and Forecast Metadata Conventions (CF Conventions) have been set for many years as the standard framework for climate data written in NetCDF format. While they allow storing unstructured data simply as data defined at a series of points, they do not currently address the topology of the underlying unstructured mesh. However, it is often necessary to have additional mesh topology information, i.e. is it a one dimensional network, a 2D triangular mesh or a flexible mixed triangle/quadrilateral mesh, a 2D mesh with vertical layers, or a fully unstructured 3D mesh. The UGRID Conventions proposed by the UGRID Interoperability group are attempting to fill in this void by extending the CF Conventions with topology specifications. As the UGRID Conventions are increasingly popular with an important subset of the CF community, they warrant the development of a customized tool for the visualization and exploration of UGRID-conforming data. The implementation of the UGRID Reader has been designed corresponding to the ParaView plugin architecture. This approach allowed us to tap into the powerful reading and rendering capabilities of ParaView, while the reader is easy to install. We aim at parallelism to be able to process large data sets. Furthermore, our current application of the reader is the visualization of higher order simulation output which demands for a special representation of the data within a cell.

"Newbies" and "Celebrities": Detecting Social Roles in an Online Network of Teachers via Participation Patterns

ERIC Educational Resources Information Center

Smith Risser, H.; Bottoms, SueAnn

2014-01-01

The advent of social networking tools allows teachers to create online networks and share information. While some virtual networks have a formal structure and defined boundaries, many do not. These unstructured virtual networks are difficult to study because they lack defined boundaries and a formal structure governing leadership roles and the…

Edge strand engineering prevents native-like aggregation in Sulfolobus solfataricus acylphosphatase.

PubMed

de Rosa, Matteo; Bemporad, Francesco; Pellegrino, Sara; Chiti, Fabrizio; Bolognesi, Martino; Ricagno, Stefano

2014-09-01

β-proteins are constantly threatened by the risk of aggregation because β-sheets are inherently structured for edge-to-edge interactions. To avoid native-like aggregation, evolution has resulted in a set of strategies that prevent intermolecular β-interactions. Acylphosphatase from Sulfolobus solfataricus (Sso AcP) represents a suitable model for the study of such a process. Under conditions promoting aggregation, Sso AcP acquires a native-like conformational state whereby an unstructured N-terminal segment interacts with the edge β-strand B4 of an adjacent Sso AcP molecule. Because B4 is poorly protected against aggregation, this interaction triggers the aggregation cascade without the need for unfolding. Recently, three single Sso AcP mutants (V84D, Y86E and V84P) were designed to engineer additional protection against aggregation in B4 and were observed to successfully impair native-like aggregation in all three variants at the expense of a lower stability. To understand the structural basis of the reduced aggregation propensity and lower stability, the crystal structures of the Sso AcP variants were determined in the present study. Structural analysis reveals that the V84D and Y86E mutations exert protection by the insertion of an edge negative charge. A conformationally less regular B4 underlies protection against aggregation in the V84P mutant. The thermodynamic basis of instability is discussed. Moreover, kinetic experiments indicate that aggregation of the three mutants is not native-like and is independent of the interaction between B4 and the unstructured N-terminal segment. The reported data rationalize previous evidence regarding Sso AcP native-like aggregation and provide a basis for the design of aggregation-free proteins. The atomic coordinates and related experimental data for the Sso AcP mutants V84P, V84D, ΔN11 Y86E have been deposited in the Protein Data Bank under accession numbers 4OJ3, 4OJG and 4OJH, respectively. • Sso AcP and Sso AcP bind by fluorescence technology (View interaction). © 2014 FEBS.

Peer-to-Peer Content Distribution and Over-The-Top TV: An Analysis of Value Networks

NASA Astrophysics Data System (ADS)

de Boever, Jorn; de Grooff, Dirk

The convergence of Internet and TV, i.e., the Over-The-Top TV (OTT TV) paradigm, created opportunities for P2P content distribution as these systems reduce bandwidth expenses for media companies. This resulted in the arrival of legal, commercial P2P systems which increases the importance of studying economic aspects of these business operations. This chapter examines the value networks of three cases (Kontiki, Zattoo and bittorrent) in order to compare how different actors position and distinguish themselves from competitors by creating value in different ways. The value networks of legal systems have different compositions depending on their market orientation - Business-to-Business (B2B) and/or Businessto- Consumer (B2C). In addition, legal systems differ from illegal systems as legal companies are not inclined to grant control to users, whereas users havemost control in value networks of illegal, self-organizing file sharing communities. In conclusion, the OTT TV paradigm made P2P technology a partner for the media industry rather than an enemy. However, we argue that the lack of control granted to users will remain a seed-bed for the success of illegal P2P file sharing communities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Guanhua; Eidenbenz, Stephan; Ha, Duc T

Botnets, which are networks of compromised machines that are controlled by one or a group of attackers, have emerged as one of the most serious security threats on the Internet. With an army of bots at the scale of tens of thousands of hosts or even as large as 1.5 million PCs, the computational power of botnets can be leveraged to launch large-scale DDoS (Distributed Denial of Service) attacks, sending spamming emails, stealing identities and financial information, etc. As detection and mitigation techniques against botnets have been stepped up in recent years, attackers are also constantly improving their strategies tomore » operate these botnets. The first generation of botnets typically employ IRC (Internet Relay Chat) channels as their command and control (C&C) centers. Though simple and easy to deploy, the centralized C&C mechanism of such botnets has made them prone to being detected and disabled. Against this backdrop, peer-to-peer (P2P) based botnets have emerged as a new generation of botnets which can conceal their C&C communication. Recently, P2P networks have emerged as a covert communication platform for malicious programs known as bots. As popular distributed systems, they allow bots to communicate easily while protecting the botmaster from being discovered. Existing work on P2P-based hotnets mainly focuses on measurement of botnet sizes. In this work, through simulation, we study extensively the structure of P2P networks running Kademlia, one of a few widely used P2P protocols in practice. Our simulation testbed incorporates the actual code of a real Kademlia client software to achieve great realism, and distributed event-driven simulation techniques to achieve high scalability. Using this testbed, we analyze the scaling, reachability, clustering, and centrality properties of P2P-based botnets from a graph-theoretical perspective. We further demonstrate experimentally and theoretically that monitoring bot activities in a P2P network is difficult, suggesting that the P2P mechanism indeed helps botnets hide their communication effectively. Finally, we evaluate the effectiveness of some potential mitigation techniques, such as content poisoning, Sybil-based and Eclipse-based mitigation. Conclusions drawn from this work shed light on the structure of P2P botnets, how to monitor bot activities in P2P networks, and how to mitigate botnet operations effectively.« less

Interaction Network of Proteins Associated with Human Cytomegalovirus IE2-p86 Protein during Infection: A Proteomic Analysis

PubMed Central

Du, Guixin; Stinski, Mark F.

2013-01-01

Human cytomegalovirus protein IE2-p86 exerts its functions through interaction with other viral and cellular proteins. To further delineate its protein interaction network, we generated a recombinant virus expressing SG-tagged IE2-p86 and used tandem affinity purification coupled with mass spectrometry. A total of 9 viral proteins and 75 cellular proteins were found to associate with IE2-p86 protein during the first 48 hours of infection. The protein profile at 8, 24, and 48 h post infection revealed that UL84 tightly associated with IE2-p86, and more viral and cellular proteins came into association with IE2-p86 with the progression of virus infection. A computational analysis of the protein-protein interaction network indicated that all of the 9 viral proteins and most of the cellular proteins identified in the study are interconnected to varying degrees. Of the cellular proteins that were confirmed to associate with IE2-p86 by immunoprecipitation, C1QBP was further shown to be upregulated by HCMV infection and colocalized with IE2-p86, UL84 and UL44 in the virus replication compartment of the nucleus. The IE2-p86 interactome network demonstrated the temporal development of stable and abundant protein complexes that associate with IE2-p86 and provided a framework to benefit future studies of various protein complexes during HCMV infection. PMID:24358118

Wakefield Simulation of CLIC PETS Structure Using Parallel 3D Finite Element Time-Domain Solver T3P

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candel, A.; Kabel, A.; Lee, L.

In recent years, SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic time-domain code T3P. Higher-order Finite Element methods on conformal unstructured meshes and massively parallel processing allow unprecedented simulation accuracy for wakefield computations and simulations of transient effects in realistic accelerator structures. Applications include simulation of wakefield damping in the Compact Linear Collider (CLIC) power extraction and transfer structure (PETS).

Effects of Weaning and Spatial Enrichment on Behavior of Turkish Saanen Goat Kids.

PubMed

Tölü, Cemil; Göktürk, Semra; Sava, Türker

2016-06-01

As is in all economic activities, the highest yield per unit area is the main goal in animal production, while addressing the temperamental needs of animals often is ignored. Animal welfare is not only an ethical fact; it also has an economic value. Spatial environmental enrichment contributes positively to animal welfare by addressing their behavioral and mental requirements. The present study was conducted to determine the effects of weaning and spatial environmental arrangements on behaviors of goat-kids. Experimental groups were arranged in structured and unstructured spatial environments. Roughage feeder, semi-automatic concentrate feeder, bunk, bridge, and wood block were placed in the structured environment. No equipment was placed in the unstructured environment and paddock sides were enclosed with an iron sheet to prevent bipedal stance and to provide environmental isolation. In the study 10 male and 10 female Turkish Saanen goat kids were used in each group. Spatial environmental arrangements did not have significant impacts on the growth performance of kids (p>0.05). All objects in the structured group were accepted by the kids. Average use ratios of roughage feeder, semi-automatic concentrate feeder, bunk, bridge and wood block were observed as 19.3%, 14.0%, 12.6%, 3.8%, and 0.7%, respectively. There were significant differences between before- and after-weaning in use of all objects except for underneath bridge (p≤0.05). Concentrate feed consumption, locomotion, and resting behaviors in kids showed significant differences by structural group and growth period. Roughage consumption was similar between groups, while it differed by growth period (p≤0.05). Interaction frequency was significantly higher in structured group (p = 0.0023). Playing behavior significantly differentiated based on the growth period rather than on groups (p≤0.05). Playing behavior significantly decreased after weaning. Abnormal oral activity was significantly higher in the structured group before weaning (p≤0.05). Despite there being no installations facilitating climbing and bipedal stance, the kids of the unstructured group were able to exhibit 1/3 as much bipedal stance behavior as the kids of the structured group through leaning over slippery paddock wall or over their groupmates. Bipedal stance behavior of unstructured group was similar before and after weaning, while bipedal stance behavior before weaning was about 2 times that of after weaning in structured group. It was concluded that unstructured environmental arrangement limited the behavior repertoire of the goat kids.

Effects of Weaning and Spatial Enrichment on Behavior of Turkish Saanen Goat Kids

PubMed Central

Tölü, Cemil; Göktürk, Semra; Sava, Türker

2016-01-01

As is in all economic activities, the highest yield per unit area is the main goal in animal production, while addressing the temperamental needs of animals often is ignored. Animal welfare is not only an ethical fact; it also has an economic value. Spatial environmental enrichment contributes positively to animal welfare by addressing their behavioral and mental requirements. The present study was conducted to determine the effects of weaning and spatial environmental arrangements on behaviors of goat-kids. Experimental groups were arranged in structured and unstructured spatial environments. Roughage feeder, semi-automatic concentrate feeder, bunk, bridge, and wood block were placed in the structured environment. No equipment was placed in the unstructured environment and paddock sides were enclosed with an iron sheet to prevent bipedal stance and to provide environmental isolation. In the study 10 male and 10 female Turkish Saanen goat kids were used in each group. Spatial environmental arrangements did not have significant impacts on the growth performance of kids (p>0.05). All objects in the structured group were accepted by the kids. Average use ratios of roughage feeder, semi-automatic concentrate feeder, bunk, bridge and wood block were observed as 19.3%, 14.0%, 12.6%, 3.8%, and 0.7%, respectively. There were significant differences between before- and after-weaning in use of all objects except for underneath bridge (p≤0.05). Concentrate feed consumption, locomotion, and resting behaviors in kids showed significant differences by structural group and growth period. Roughage consumption was similar between groups, while it differed by growth period (p≤0.05). Interaction frequency was significantly higher in structured group (p = 0.0023). Playing behavior significantly differentiated based on the growth period rather than on groups (p≤0.05). Playing behavior significantly decreased after weaning. Abnormal oral activity was significantly higher in the structured group before weaning (p≤0.05). Despite there being no installations facilitating climbing and bipedal stance, the kids of the unstructured group were able to exhibit 1/3 as much bipedal stance behavior as the kids of the structured group through leaning over slippery paddock wall or over their groupmates. Bipedal stance behavior of unstructured group was similar before and after weaning, while bipedal stance behavior before weaning was about 2 times that of after weaning in structured group. It was concluded that unstructured environmental arrangement limited the behavior repertoire of the goat kids. PMID:26954169

Study of the GPS inter-frequency calibration of timing receivers

NASA Astrophysics Data System (ADS)

Defraigne, P.; Huang, W.; Bertrand, B.; Rovera, D.

2018-02-01

When calibrating Global Positioning System (GPS) stations dedicated to timing, the hardware delays of P1 and P2, the P(Y)-codes on frequencies L1 and L2, are determined separately. In the international atomic time (TAI) network the GPS stations of the time laboratories are calibrated relatively against reference stations. This paper aims at determining the consistency between the P1 and P2 hardware delays (called dP1 and dP2) of these reference stations, and to look at the stability of the inter-signal hardware delays dP1-dP2 of all the stations in the network. The method consists of determining the dP1-dP2 directly from the GPS pseudorange measurements corrected for the frequency-dependent antenna phase center and the frequency-dependent ionosphere corrections, and then to compare these computed dP1-dP2 to the calibrated values. Our results show that the differences between the computed and calibrated dP1-dP2 are well inside the expected combined uncertainty of the two quantities. Furthermore, the consistency between the calibrated time transfer solution obtained from either single-frequency P1 or dual-frequency P3 for reference laboratories is shown to be about 1.0 ns, well inside the 2.1 ns uB uncertainty of a time transfer link based on GPS P3 or Precise Point Positioning. This demonstrates the good consistency between the P1 and P2 hardware delays of the reference stations used for calibration in the TAI network. The long-term stability of the inter-signal hardware delays is also analysed from the computed dP1-dP2. It is shown that only variations larger than 2 ns can be detected for a particular station, while variations of 200 ps can be detected when differentiating the results between two stations. Finally, we also show that in the differential calibration process as used in the TAI network, using the same antenna phase center or using different positions for L1 and L2 signals gives maximum differences of 200 ps on the hardware delays of the separate codes P1 and P2; however, the final impact on the P3 combination is less than 10 ps.

Technological Networks

NASA Astrophysics Data System (ADS)

Mitra, Bivas

The study of networks in the form of mathematical graph theory is one of the fundamental pillars of discrete mathematics. However, recent years have witnessed a substantial new movement in network research. The focus of the research is shifting away from the analysis of small graphs and the properties of individual vertices or edges to consideration of statistical properties of large scale networks. This new approach has been driven largely by the availability of technological networks like the Internet [12], World Wide Web network [2], etc. that allow us to gather and analyze data on a scale far larger than previously possible. At the same time, technological networks have evolved as a socio-technological system, as the concepts of social systems that are based on self-organization theory have become unified in technological networks [13]. In today’s society, we have a simple and universal access to great amounts of information and services. These information services are based upon the infrastructure of the Internet and the World Wide Web. The Internet is the system composed of ‘computers’ connected by cables or some other form of physical connections. Over this physical network, it is possible to exchange e-mails, transfer files, etc. On the other hand, the World Wide Web (commonly shortened to the Web) is a system of interlinked hypertext documents accessed via the Internet where nodes represent web pages and links represent hyperlinks between the pages. Peer-to-peer (P2P) networks [26] also have recently become a popular medium through which huge amounts of data can be shared. P2P file sharing systems, where files are searched and downloaded among peers without the help of central servers, have emerged as a major component of Internet traffic. An important advantage in P2P networks is that all clients provide resources, including bandwidth, storage space, and computing power. In this chapter, we discuss these technological networks in detail. The review is organized as follows. Section 2 presents an introduction to the Internet and different protocols related to it. This section also specifies the socio-technological properties of the Internet, like scale invariance, the small-world property, network resilience, etc. Section 3 describes the P2P networks, their categorization, and other related issues like search, stability, etc. Section 4 concludes the chapter.

Social networks to biological networks: systems biology of Mycobacterium tuberculosis.

PubMed

Vashisht, Rohit; Bhardwaj, Anshu; Osdd Consortium; Brahmachari, Samir K

2013-07-01

Contextualizing relevant information to construct a network that represents a given biological process presents a fundamental challenge in the network science of biology. The quality of network for the organism of interest is critically dependent on the extent of functional annotation of its genome. Mostly the automated annotation pipelines do not account for unstructured information present in volumes of literature and hence large fraction of genome remains poorly annotated. However, if used, this information could substantially enhance the functional annotation of a genome, aiding the development of a more comprehensive network. Mining unstructured information buried in volumes of literature often requires manual intervention to a great extent and thus becomes a bottleneck for most of the automated pipelines. In this review, we discuss the potential of scientific social networking as a solution for systematic manual mining of data. Focusing on Mycobacterium tuberculosis, as a case study, we discuss our open innovative approach for the functional annotation of its genome. Furthermore, we highlight the strength of such collated structured data in the context of drug target prediction based on systems level analysis of pathogen.

Robustness of a network formed by n interdependent networks with a one-to-one correspondence of dependent nodes.

PubMed

Gao, Jianxi; Buldyrev, S V; Havlin, S; Stanley, H E

2012-06-01

Many real-world networks interact with and depend upon other networks. We develop an analytical framework for studying a network formed by n fully interdependent randomly connected networks, each composed of the same number of nodes N. The dependency links connecting nodes from different networks establish a unique one-to-one correspondence between the nodes of one network and the nodes of the other network. We study the dynamics of the cascades of failures in such a network of networks (NON) caused by a random initial attack on one of the networks, after which a fraction p of its nodes survives. We find for the fully interdependent loopless NON that the final state of the NON does not depend on the dynamics of the cascades but is determined by a uniquely defined mutual giant component of the NON, which generalizes both the giant component of regular percolation of a single network (n=1) and the recently studied case of the mutual giant component of two interdependent networks (n=2). We also find that the mutual giant component does not depend on the topology of the NON and express it in terms of generating functions of the degree distributions of the network. Our results show that, for any n≥2 there exists a critical p=p(c)>0 below which the mutual giant component abruptly collapses from a finite nonzero value for p≥p(c) to zero for p2, a RR NON is stable for any n with p(c)<1). This results arises from the critical role played by singly connected nodes which exist in an ER NON and enhance the cascading failures, but do not exist in a RR NON.

Isolation and Compositional Analysis of a CP12-Associated Complex of Calvin Cycle Enzymes from Nicotiana tabacum

USDA-ARS?s Scientific Manuscript database

CP12 is a small intrinsically unstructured protein that forms a multiprotein complex with two Calvin Cycle enzymes, phosphoribulokinase (PRK) and NAD(P)-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The complex can be reconstituted in vitro from recombinant proteins under conditions t...

pH-Responsive Shape Memory Poly(ethylene glycol)-Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite.

PubMed

Li, Ying; Chen, Hongmei; Liu, Dian; Wang, Wenxi; Liu, Ye; Zhou, Shaobing

2015-06-17

In this study, we developed a pH-responsive shape-memory polymer nanocomposite by blending poly(ethylene glycol)-poly(ε-caprolactone)-based polyurethane (PECU) with functionalized cellulose nanocrystals (CNCs). CNCs were functionalized with pyridine moieties (CNC-C6H4NO2) through hydroxyl substitution of CNCs with pyridine-4-carbonyl chloride and with carboxyl groups (CNC-CO2H) via 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) mediated surface oxidation, respectively. At a high pH value, the CNC-C6H4NO2 had attractive interactions from the hydrogen bonding between pyridine groups and hydroxyl moieties; at a low pH value, the interactions reduced or disappeared due to the protonation of pyridine groups, which are a Lewis base. The CNC-CO2H responded to pH variation in an opposite manner. The hydrogen bonding interactions of both CNC-C6H4NO2 and CNC-CO2H can be readily disassociated by altering pH values, endowing the pH-responsiveness of CNCs. When these functionalized CNCs were added in PECU polymer matrix to form nanocomposite network which was confirmed with rheological measurements, the mechanical properties of PECU were not only obviously improved but also the pH-responsiveness of CNCs could be transferred to the nanocomposite network. The pH-sensitive CNC percolation network in polymer matrix served as the switch units of shape-memory polymers (SMPs). Furthermore, the modified CNC percolation network and polymer molecular chains also had strong hydrogen bonding interactions among hydroxyl, carboxyl, pyridine moieties, and isocyanate groups, which could be formed or destroyed through changing pH value. The shape memory function of the nanocomposite network was only dependent on the pH variation of the environment. Therefore, this pH-responsive shape-memory nancomposite could be potentially developed into a new smart polymer material.

Network Science Center Research Team’s Visit to Kampala, Uganda

DTIC Science & Technology

2013-07-01

Religious Leader • Someone in Social Network • Commercial Bank • White Collar Professional • Military Leader 18 | P a g e Network Science...relationship between the person under analysis and the people within the social network (Van Der Gaag & Snijders, 2004). 2 | P a g e Network...energetic and tech savvy. 3 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 Our team’s next data collection effort

Numerical Experiments on Advective Transport in Large Three-Dimensional Discrete Fracture Networks

NASA Astrophysics Data System (ADS)

Makedonska, N.; Painter, S. L.; Karra, S.; Gable, C. W.

2013-12-01

Modeling of flow and solute transport in discrete fracture networks is an important approach for understanding the migration of contaminants in impermeable hard rocks such as granite, where fractures provide dominant flow and transport pathways. The discrete fracture network (DFN) model attempts to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. An integrated DFN meshing [1], flow, and particle tracking [2] simulation capability that enables accurate flow and particle tracking simulation on large DFNs has recently been developed. The new capability has been used in numerical experiments on advective transport in large DFNs with tens of thousands of fractures and millions of computational cells. The modeling procedure starts from the fracture network generation using a stochastic model derived from site data. A high-quality computational mesh is then generated [1]. Flow is then solved using the highly parallel PFLOTRAN [3] code. PFLOTRAN uses the finite volume approach, which is locally mass conserving and thus eliminates mass balance problems during particle tracking. The flow solver provides the scalar fluxes on each control volume face. From the obtained fluxes the Darcy velocity is reconstructed for each node in the network [4]. Velocities can then be continuously interpolated to any point in the domain of interest, thus enabling random walk particle tracking. In order to describe the flow field on fractures intersections, the control volume cells on intersections are split into four planar polygons, where each polygon corresponds to a piece of a fracture near the intersection line. Thus, computational nodes lying on fracture intersections have four associated velocities, one on each side of the intersection in each fracture plane [2]. This information is used to route particles arriving at the fracture intersection to the appropriate downstream fracture segment. Verified for small DFNs, the new simulation capability allows accurate particle tracking on more realistic representations of fractured rock sites. In the current work we focus on travel time statistics and spatial dispersion and show numerical results in DFNs of different sizes, fracture densities, and transmissivity distributions. [1] Hyman J.D., Gable C.W., Painter S.L., Automated meshing of stochastically generated discrete fracture networks, Abstract H33G-1403, 2011 AGU, San Francisco, CA, 5-9 Dec. [2] N. Makedonska, S. L. Painter, T.-L. Hsieh, Q.M. Bui, and C. W. Gable., Development and verification of a new particle tracking capability for modeling radionuclide transport in discrete fracture networks, Abstract, 2013 IHLRWM, Albuquerque, NM, Apr. 28 - May 3. [3] Lichtner, P.C., Hammond, G.E., Bisht, G., Karra, S., Mills, R.T., and Kumar, J. (2013) PFLOTRAN User's Manual: A Massively Parallel Reactive Flow Code. [4] Painter S.L., Gable C.W., Kelkar S., Pathline tracing on fully unstructured control-volume grids, Computational Geosciences, 16 (4), 2012, 1125-1134.

Use of sentiment analysis for capturing patient experience from free-text comments posted online.

PubMed

Greaves, Felix; Ramirez-Cano, Daniel; Millett, Christopher; Darzi, Ara; Donaldson, Liam

2013-11-01

There are large amounts of unstructured, free-text information about quality of health care available on the Internet in blogs, social networks, and on physician rating websites that are not captured in a systematic way. New analytical techniques, such as sentiment analysis, may allow us to understand and use this information more effectively to improve the quality of health care. We attempted to use machine learning to understand patients' unstructured comments about their care. We used sentiment analysis techniques to categorize online free-text comments by patients as either positive or negative descriptions of their health care. We tried to automatically predict whether a patient would recommend a hospital, whether the hospital was clean, and whether they were treated with dignity from their free-text description, compared to the patient's own quantitative rating of their care. We applied machine learning techniques to all 6412 online comments about hospitals on the English National Health Service website in 2010 using Weka data-mining software. We also compared the results obtained from sentiment analysis with the paper-based national inpatient survey results at the hospital level using Spearman rank correlation for all 161 acute adult hospital trusts in England. There was 81%, 84%, and 89% agreement between quantitative ratings of care and those derived from free-text comments using sentiment analysis for cleanliness, being treated with dignity, and overall recommendation of hospital respectively (kappa scores: .40-.74, P<.001 for all). We observed mild to moderate associations between our machine learning predictions and responses to the large patient survey for the three categories examined (Spearman rho 0.37-0.51, P<.001 for all). The prediction accuracy that we have achieved using this machine learning process suggests that we are able to predict, from free-text, a reasonably accurate assessment of patients' opinion about different performance aspects of a hospital and that these machine learning predictions are associated with results of more conventional surveys.

Dielectric and diamagnetic susceptibilities near percolative superconductor-insulator transitions

NASA Astrophysics Data System (ADS)

Loh, Yen Lee; Karki, Pragalv

2017-10-01

Coarse-grained superconductor-insulator composites exhibit a superconductor-insulator transition governed by classical percolation, which should be describable by networks of inductors and capacitors. We study several classes of random inductor-capacitor networks on square lattices. We present a unifying framework for defining electric and magnetic response functions, and we extend the Frank-Lobb bond-propagation algorithm to compute these quantities by network reduction. We confirm that the superfluid stiffness scales approximately as ( p-p_c){\\hspace{0pt}}1.3 as the superconducting bond fraction p approaches the percolation threshold p c . We find that the diamagnetic susceptibility scales as ( p_c-p){\\hspace{0pt}}-1.3 below percolation, and as L2 ( p-p_c){\\hspace{0pt}}1.3 above percolation. For models lacking self-capacitances, the electric susceptibility scales as ( p_c-p){\\hspace{0pt}}-1.3 . Including a self-capacitance on each node changes the critical behavior to approximately ( p_c-p){\\hspace{0pt}}-2.52 .

Network Science Center Research Team’s Visit to Kampala, Uganda

DTIC Science & Technology

2013-07-01

Commercial Bank • White Collar Professional • Military Leader 18 | P a g e Network Science Center, West Point www.netscience.usma.edu...people within the social network (Van Der Gaag & Snijders, 2004). 2 | P a g e Network Science Center, West Point www.netscience.usma.edu...University, one of the leading universities in Sub-Saharan Africa. The student body is energetic and tech savvy. 3 | P a g e Network Science

Distortion of online reputation by excess reciprocity: quantification and estimation of unbiased reputation

NASA Astrophysics Data System (ADS)

Aste, Tomaso; Livan, Giacomo; Caccioli, Fabio

The peer-to-peer (P2P) economy relies on establishing trust in distributed networked systems, where the reliability of a user is assessed through digital peer-review processes that aggregate ratings into reputation scores. Here we present evidence of a network effect which biases digital reputations, revealing that P2P networks display exceedingly high levels of reciprocity. In fact, these are so large that they are close to the highest levels structurally compatible with the networks reputation landscape. This indicates that the crowdsourcing process underpinning digital reputation is significantly distorted by the attempt of users to mutually boost reputation, or to retaliate, through the exchange of ratings. We uncover that the least active users are predominantly responsible for such reciprocity-induced bias, and that this fact can be exploited to obtain more reliable reputation estimates. Our findings are robust across different P2P platforms, including both cases where ratings are used to vote on the content produced by users and to vote on user profiles.

Probing the Role of Nascent Helicity in p27 Function as a Cell Cycle Regulator

PubMed Central

Otieno, Steve; Kriwacki, Richard

2012-01-01

p27 regulates the activity of Cdk complexes which are the principal governors of phase transitions during cell division. Members of the p27 family of proteins, which also includes p21 and p57, are called the Cip/Kip cyclin-dependent kinase regulators (CKRs). Interestingly, the Cip/Kip CKRs play critical roles in cell cycle regulation by being intrinsically unstructured, a characteristic contrary to the classical structure-function paradigm. They exhibit nascent helicity which has been localized to a segment referred to as sub-domain LH. The nascent helicity of this sub-domain is conserved and we hypothesize that it is an important determinant of their functional properties. To test this hypothesis, we successfully designed and prepared p27 variants in which domain LH was either more or less helical with respect to the wild-type protein. Thermal denaturation experiments showed that the ternary complexes of the p27 variants bound to Cdk2/Cyclin A were less stable compared to the wild-type complex. Isothermal titration calorimetry experiments showed a decrease in the enthalpy of binding for all the mutants with respect to p27. The free energies of binding varied within a much narrower range. In vitro Cdk2 inhibition assays showed that the p27 variants exhibited disparate inhibitory potencies. Furthermore, when over-expressed in NIH 3T3 mouse fibroblast cells, the less helical p27 variants were less effective in causing cell cycle arrest relative to the wild-type p27. Our results indicate that the nascent helicity of sub-domain LH plays a key role mediating the biological function of p27. PMID:23071750

A long-reach WDM passive optical network enabling broadcasting service with centralized light source

NASA Astrophysics Data System (ADS)

Liu, D.; Tang, M.; Fu, S.; Liu, D.; Shum, P.

2012-02-01

We propose a long-reach wavelength-division-multiplexed (WDM) passive optical network (PON) to provide conventional point-to-point (P2P) data and downstream broadcasting service simultaneously by superimposing, for each WDM channel, the differential-phase-shift-keying (DPSK) broadcasting signal with the subcarrier multiplexing (SCM) modulated downstream P2P signal, at the optical line terminal (OLT). In the optical network units (ONUs), by re-modulating part of the downstream signal with a reflective semiconductor optical amplifier (RSOA), we realize color-less ONUs for upstream data transmission. The proposed scheme is numerically verified with a 5 Gb/s downstream P2P signal and broadcasting services, as well as 2.5 Gb/s upstream data through a 60 km bidirectional fiber link. In particular, the influence of the downstream lightwave's optical carrier-subcarrier ratio (OCSR) on the system performance is also investigated.

State of the Art in Trust and Reputation Models in P2P networks

NASA Astrophysics Data System (ADS)

Mármol, Félix Gómez; Pérez, Gregorio Martínez

Ensuring security in a distributed environment such as P2P networks is a critical issue nowadays. Nevertheless, it is in those kind of scenarios in which entities can enter or leave the community whenever they want, where traditional mboxsecurity schemes can not always be applied. Specifically, the use of a PKI (Public Key Infrastructure) may be unacceptable within highly distributed systems. Therefore, modeling concepts like trust and reputation may result very helpful and useful when trying to gain a certain level of security and confidence among inter-operating entities. Thus, this chapter presents a review of some of the most representative trust and reputation models for P2P networks, discussing their main characteristics and also their weaknesses and deficiencies. Open issues and challenges associated with them will be also covered.

Wave Transformation Over Reefs: Evaluation of One-Dimensional Numerical Models

DTIC Science & Technology

2009-01-01

equations on an unstructured grid. Proceedings International Conference on Coastal Engineering ‘06 V1. San Diego, CA, 73-85. Baldock, T. E., P. Holmes , S...equations. Monthly Weather Review 91:99-164. Smith, J. M, A. R. Sherlock , and D. T. Resio. 2001. Steady state spectral wave model user’s manual

Numerical Simulations of Aero-Optical Distortions Around Various Turret Geometries

DTIC Science & Technology

2013-06-12

arbi trary cell topologies. The spatial operator uses the exact Riemann Solver of Gottlieb and Groth, least squares gradient cal- culations using QR...Unstructured Euler/Navier-Stokes Flow Solver ," in A/AA Paper 1999-0786, 1999. [9] J. J. Gottlieb and C. P. T. Groth, "Assessment of Riemann Solvers

Peer-to-Peer Science Data Environment

NASA Astrophysics Data System (ADS)

Byrnes, J. B.; Holland, M. P.

2004-12-01

The goal of P2PSDE is to provide a convenient and extensible Peer-to-Peer (P2P) network architecture that allows: distributed science-data services-seamlessly incorporating collaborative value-added services with search-oriented access to remote science data. P2PSDE features the real-time discovery of data-serving peers (plus peer-groups and peer-group services), in addition to the searching for and transferring of science data. These features are implemented using "Project JXTA", the first and only standardized set of open, generalized P2P protocols that allow arbitrary network devices to communicate and collaborate as peers. The JXTA protocols standardize the manner in which peers discover each other, self-organize into peer groups, advertise and discover network services, and securely communicate with and monitor each other-even across network firewalls. The key benefits include: Potential for dramatic improvements in science-data dissemination; Real-time-discoverable, potentially redundant (reliable), science-data services; Openness/Extensibility; Decentralized use of small, inexpensive, readily-available desktop machines; and Inherently secure-with ability to create variable levels of security by group.

Load Balancing in Structured P2P Networks

NASA Astrophysics Data System (ADS)

Zhu, Yingwu

In this chapter we start by addressing the importance and necessity of load balancing in structured P2P networks, due to three main reasons. First, structured P2P networks assume uniform peer capacities while peer capacities are heterogeneous in deployed P2P networks. Second, resorting to pseudo-uniformity of the hash function used to generate node IDs and data item keys leads to imbalanced overlay address space and item distribution. Lastly, placement of data items cannot be randomized in some applications (e.g., range searching). We then present an overview of load aggregation and dissemination techniques that are required by many load balancing algorithms. Two techniques are discussed including tree structure-based approach and gossip-based approach. They make different tradeoffs between estimate/aggregate accuracy and failure resilience. To address the issue of load imbalance, three main solutions are described: virtual server-based approach, power of two choices, and address-space and item balancing. While different in their designs, they all aim to improve balance on the address space and data item distribution. As a case study, the chapter discusses a virtual server-based load balancing algorithm that strives to ensure fair load distribution among nodes and minimize load balancing cost in bandwidth. Finally, the chapter concludes with future research and a summary.

P-HARP: A parallel dynamic spectral partitioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sohn, A.; Biswas, R.; Simon, H.D.

1997-05-01

Partitioning unstructured graphs is central to the parallel solution of problems in computational science and engineering. The authors have introduced earlier the sequential version of an inertial spectral partitioner called HARP which maintains the quality of recursive spectral bisection (RSB) while forming the partitions an order of magnitude faster than RSB. The serial HARP is known to be the fastest spectral partitioner to date, three to four times faster than similar partitioners on a variety of meshes. This paper presents a parallel version of HARP, called P-HARP. Two types of parallelism have been exploited: loop level parallelism and recursive parallelism.more » P-HARP has been implemented in MPI on the SGI/Cray T3E and the IBM SP2. Experimental results demonstrate that P-HARP can partition a mesh of over 100,000 vertices into 256 partitions in 0.25 seconds on a 64-processor T3E. Experimental results further show that P-HARP can give nearly a 20-fold speedup on 64 processors. These results indicate that graph partitioning is no longer a major bottleneck that hinders the advancement of computational science and engineering for dynamically-changing real-world applications.« less

Network Science Center Research Team’s Visit to Kampala, Uganda

DTIC Science & Technology

2013-04-15

Leader • Someone in Social Network • Commercial Bank • White Collar Professional • Military Leader 16 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 ...regions, where the Lord’s Resistance Army 2 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 (LRA), a militant...Non-Governmental Organizations. Teddy Ruge Kanjokya Road in Kamwokya 3 | P a g e Network Science Center, West Point

Dynamic Rupture Benchmarking of the ADER-DG Method

NASA Astrophysics Data System (ADS)

Gabriel, Alice; Pelties, Christian

2013-04-01

We will verify the arbitrary high-order derivative Discontinuous Galerkin (ADER-DG) method in various test cases of the 'SCEC/USGS Dynamic Earthquake Rupture Code Verification Exercise' benchmark suite (Harris et al. 2009). The ADER-DG scheme is able to solve the spontaneous rupture problem with high-order accuracy in space and time on three-dimensional unstructured tetrahedral meshes. Strong mesh coarsening or refinement at areas of interest can be applied to keep the computational costs feasible. Moreover, the method does not generate spurious high-frequency contributions in the slip rate spectra and therefore does not require any artificial damping as demonstrated in previous presentations and publications (Pelties et al. 2010 and 2012). We will show that the mentioned features hold also for more advanced setups as e.g. a branching fault system, heterogeneous background stresses and bimaterial faults. The advanced geometrical flexibility combined with an enhanced accuracy will make the ADER-DG method a useful tool to study earthquake dynamics on complex fault systems in realistic rheologies. References: Harris, R.A., M. Barall, R. Archuleta, B. Aagaard, J.-P. Ampuero, H. Bhat, V. Cruz-Atienza, L. Dalguer, P. Dawson, S. Day, B. Duan, E. Dunham, G. Ely, Y. Kaneko, Y. Kase, N. Lapusta, Y. Liu, S. Ma, D. Oglesby, K. Olsen, A. Pitarka, S. Song, and E. Templeton, The SCEC/USGS Dynamic Earthquake Rupture Code Verification Exercise, Seismological Research Letters, vol. 80, no. 1, pages 119-126, 2009 Pelties, C., J. de la Puente, and M. Kaeser, Dynamic Rupture Modeling in Three Dimensions on Unstructured Meshes Using a Discontinuous Galerkin Method, AGU 2010 Fall Meeting, abstract #S21C-2068 Pelties, C., J. de la Puente, J.-P. Ampuero, G. Brietzke, and M. Kaeser, Three-Dimensional Dynamic Rupture Simulation with a High-order Discontinuous Galerkin Method on Unstructured Tetrahedral Meshes, JGR. - Solid Earth, VOL. 117, B02309, 2012

Dynamic Rupture Benchmarking of the ADER-DG Method

NASA Astrophysics Data System (ADS)

Pelties, C.; Gabriel, A.

2012-12-01

We will verify the arbitrary high-order derivative Discontinuous Galerkin (ADER-DG) method in various test cases of the 'SCEC/USGS Dynamic Earthquake Rupture Code Verification Exercise' benchmark suite (Harris et al. 2009). The ADER-DG scheme is able to solve the spontaneous rupture problem with high-order accuracy in space and time on three-dimensional unstructured tetrahedral meshes. Strong mesh coarsening or refinement at areas of interest can be applied to keep the computational costs feasible. Moreover, the method does not generate spurious high-frequency contributions in the slip rate spectra and therefore does not require any artificial damping as demonstrated in previous presentations and publications (Pelties et al. 2010 and 2012). We will show that the mentioned features hold also for more advanced setups as e.g. a branching fault system, heterogeneous background stresses and bimaterial faults. The advanced geometrical flexibility combined with an enhanced accuracy will make the ADER-DG method a useful tool to study earthquake dynamics on complex fault systems in realistic rheologies. References: Harris, R.A., M. Barall, R. Archuleta, B. Aagaard, J.-P. Ampuero, H. Bhat, V. Cruz-Atienza, L. Dalguer, P. Dawson, S. Day, B. Duan, E. Dunham, G. Ely, Y. Kaneko, Y. Kase, N. Lapusta, Y. Liu, S. Ma, D. Oglesby, K. Olsen, A. Pitarka, S. Song, and E. Templeton, The SCEC/USGS Dynamic Earthquake Rupture Code Verification Exercise, Seismological Research Letters, vol. 80, no. 1, pages 119-126, 2009 Pelties, C., J. de la Puente, and M. Kaeser, Dynamic Rupture Modeling in Three Dimensions on Unstructured Meshes Using a Discontinuous Galerkin Method, AGU 2010 Fall Meeting, abstract #S21C-2068 Pelties, C., J. de la Puente, J.-P. Ampuero, G. Brietzke, and M. Kaeser, Three-Dimensional Dynamic Rupture Simulation with a High-order Discontinuous Galerkin Method on Unstructured Tetrahedral Meshes, JGR. - Solid Earth, VOL. 117, B02309, 2012

Network Analysis to Risk Stratify Patients With Exercise Intolerance.

PubMed

Oldham, William M; Oliveira, Rudolf K F; Wang, Rui-Sheng; Opotowsky, Alexander R; Rubins, David M; Hainer, Jon; Wertheim, Bradley M; Alba, George A; Choudhary, Gaurav; Tornyos, Adrienn; MacRae, Calum A; Loscalzo, Joseph; Leopold, Jane A; Waxman, Aaron B; Olschewski, Horst; Kovacs, Gabor; Systrom, David M; Maron, Bradley A

2018-03-16

Current methods assessing clinical risk because of exercise intolerance in patients with cardiopulmonary disease rely on a small subset of traditional variables. Alternative strategies incorporating the spectrum of factors underlying prognosis in at-risk patients may be useful clinically, but are lacking. Use unbiased analyses to identify variables that correspond to clinical risk in patients with exercise intolerance. Data from 738 consecutive patients referred for invasive cardiopulmonary exercise testing at a single center (2011-2015) were analyzed retrospectively (derivation cohort). A correlation network of invasive cardiopulmonary exercise testing parameters was assembled using |r|>0.5. From an exercise network of 39 variables (ie, nodes) and 98 correlations (ie, edges) corresponding to P <9.5e -46 for each correlation, we focused on a subnetwork containing peak volume of oxygen consumption (pVo 2 ) and 9 linked nodes. K-mean clustering based on these 10 variables identified 4 novel patient clusters characterized by significant differences in 44 of 45 exercise measurements ( P <0.01). Compared with a probabilistic model, including 23 independent predictors of pVo 2 and pVo 2 itself, the network model was less redundant and identified clusters that were more distinct. Cluster assignment from the network model was predictive of subsequent clinical events. For example, a 4.3-fold ( P <0.0001; 95% CI, 2.2-8.1) and 2.8-fold ( P =0.0018; 95% CI, 1.5-5.2) increase in hazard for age- and pVo 2 -adjusted all-cause 3-year hospitalization, respectively, were observed between the highest versus lowest risk clusters. Using these data, we developed the first risk-stratification calculator for patients with exercise intolerance. When applying the risk calculator to patients in 2 independent invasive cardiopulmonary exercise testing cohorts (Boston and Graz, Austria), we observed a clinical risk profile that paralleled the derivation cohort. Network analyses were used to identify novel exercise groups and develop a point-of-care risk calculator. These data expand the range of useful clinical variables beyond pVo 2 that predict hospitalization in patients with exercise intolerance. © 2018 American Heart Association, Inc.

Efficient data replication for the delivery of high-quality video content over P2P VoD advertising networks

NASA Astrophysics Data System (ADS)

Ho, Chien-Peng; Yu, Jen-Yu; Lee, Suh-Yin

2011-12-01

Recent advances in modern television systems have had profound consequences for the scalability, stability, and quality of transmitted digital data signals. This is of particular significance for peer-to-peer (P2P) video-on-demand (VoD) related platforms, faced with an immediate and growing demand for reliable service delivery. In response to demands for high-quality video, the key objectives in the construction of the proposed framework were user satisfaction with perceived video quality and the effective utilization of available resources on P2P VoD networks. This study developed a peer-based promoter to support online advertising in P2P VoD networks based on an estimation of video distortion prior to the replication of data stream chunks. The proposed technology enables the recovery of lost video using replicated stream chunks in real time. Load balance is achieved by adjusting the replication level of each candidate group according to the degree-of-distortion, thereby enabling a significant reduction in server load and increased scalability in the P2P VoD system. This approach also promotes the use of advertising as an efficient tool for commercial promotion. Results indicate that the proposed system efficiently satisfies the given fault tolerances.

A text-based data mining and toxicity prediction modeling system for a clinical decision support in radiation oncology: A preliminary study

NASA Astrophysics Data System (ADS)

Kim, Kwang Hyeon; Lee, Suk; Shim, Jang Bo; Chang, Kyung Hwan; Yang, Dae Sik; Yoon, Won Sup; Park, Young Je; Kim, Chul Yong; Cao, Yuan Jie

2017-08-01

The aim of this study is an integrated research for text-based data mining and toxicity prediction modeling system for clinical decision support system based on big data in radiation oncology as a preliminary research. The structured and unstructured data were prepared by treatment plans and the unstructured data were extracted by dose-volume data image pattern recognition of prostate cancer for research articles crawling through the internet. We modeled an artificial neural network to build a predictor model system for toxicity prediction of organs at risk. We used a text-based data mining approach to build the artificial neural network model for bladder and rectum complication predictions. The pattern recognition method was used to mine the unstructured toxicity data for dose-volume at the detection accuracy of 97.9%. The confusion matrix and training model of the neural network were achieved with 50 modeled plans (n = 50) for validation. The toxicity level was analyzed and the risk factors for 25% bladder, 50% bladder, 20% rectum, and 50% rectum were calculated by the artificial neural network algorithm. As a result, 32 plans could cause complication but 18 plans were designed as non-complication among 50 modeled plans. We integrated data mining and a toxicity modeling method for toxicity prediction using prostate cancer cases. It is shown that a preprocessing analysis using text-based data mining and prediction modeling can be expanded to personalized patient treatment decision support based on big data.

PISA: Federated Search in P2P Networks with Uncooperative Peers

NASA Astrophysics Data System (ADS)

Ren, Zujie; Shou, Lidan; Chen, Gang; Chen, Chun; Bei, Yijun

Recently, federated search in P2P networks has received much attention. Most of the previous work assumed a cooperative environment where each peer can actively participate in information publishing and distributed document indexing. However, little work has addressed the problem of incorporating uncooperative peers, which do not publish their own corpus statistics, into a network. This paper presents a P2P-based federated search framework called PISA which incorporates uncooperative peers as well as the normal ones. In order to address the indexing needs for uncooperative peers, we propose a novel heuristic query-based sampling approach which can obtain high-quality resource descriptions from uncooperative peers at relatively low communication cost. We also propose an effective method called RISE to merge the results returned by uncooperative peers. Our experimental results indicate that PISA can provide quality search results, while utilizing the uncooperative peers at a low cost.

RIACS

NASA Technical Reports Server (NTRS)

Oliger, Joseph

1997-01-01

Topics considered include: high-performance computing; cognitive and perceptual prostheses (computational aids designed to leverage human abilities); autonomous systems. Also included: development of a 3D unstructured grid code based on a finite volume formulation and applied to the Navier-stokes equations; Cartesian grid methods for complex geometry; multigrid methods for solving elliptic problems on unstructured grids; algebraic non-overlapping domain decomposition methods for compressible fluid flow problems on unstructured meshes; numerical methods for the compressible navier-stokes equations with application to aerodynamic flows; research in aerodynamic shape optimization; S-HARP: a parallel dynamic spectral partitioner; numerical schemes for the Hamilton-Jacobi and level set equations on triangulated domains; application of high-order shock capturing schemes to direct simulation of turbulence; multicast technology; network testbeds; supercomputer consolidation project.

Mss11p Is a Central Element of the Regulatory Network That Controls FLO11 Expression and Invasive Growth in Saccharomyces cerevisiae

PubMed Central

van Dyk, Dewald; Pretorius, Isak S.; Bauer, Florian F.

2005-01-01

The invasive and filamentous growth forms of Saccharomyces cerevisiae are adaptations to specific environmental conditions, under particular conditions of limited nutrient availability. Both growth forms are dependent on the expression of the FLO11 gene, which encodes a cell-wall-associated glycoprotein involved in cellular adhesion. A complex regulatory network consisting of signaling pathways and transcription factors has been associated with the regulation of FLO11. Mss11p has been identified as a transcriptional activator of this gene, and here we present an extensive genetic analysis to identify functional relationships between Mss11p and other FLO11 regulators. The data show that Mss11p is absolutely required for the activation of FLO11 by most proteins that have previously been shown to affect FLO11 expression, including the signaling proteins Ras2p, Kss1p, and Tpk2p, the activators Tec1p, Flo8p, and Phd1p, and the repressors Nrg1p, Nrg2p, Sok2p, and Sfl1p. The genetic evidence furthermore suggests that Mss11p activity is not dependent on the presence of any of the above-mentioned factors and that the protein also regulates other genes involved in cellular adhesion phenotypes. Taken together, the data strongly suggest a central role for Mss11p in the regulatory network controlling FLO11 expression, invasive growth, and pseudohyphal differentiation. PMID:15466424

Characterization of contact offenders and child exploitation material trafficking on five peer-to-peer networks.

PubMed

Bissias, George; Levine, Brian; Liberatore, Marc; Lynn, Brian; Moore, Juston; Wallach, Hanna; Wolak, Janis

2016-02-01

We provide detailed measurement of the illegal trade in child exploitation material (CEM, also known as child pornography) from mid-2011 through 2014 on five popular peer-to-peer (P2P) file sharing networks. We characterize several observations: counts of peers trafficking in CEM; the proportion of arrested traffickers that were identified during the investigation as committing contact sexual offenses against children; trends in the trafficking of sexual images of sadistic acts and infants or toddlers; the relationship between such content and contact offenders; and survival rates of CEM. In the 5 P2P networks we examined, we estimate there were recently about 840,000 unique installations per month of P2P programs sharing CEM worldwide. We estimate that about 3 in 10,000 Internet users worldwide were sharing CEM in a given month; rates vary per country. We found an overall month-to-month decline in trafficking of CEM during our study. By surveying law enforcement we determined that 9.5% of persons arrested for P2P-based CEM trafficking on the studied networks were identified during the investigation as having sexually offended against children offline. Rates per network varied, ranging from 8% of arrests for CEM trafficking on Gnutella to 21% on BitTorrent. Within BitTorrent, where law enforcement applied their own measure of content severity, the rate of contact offenses among peers sharing the most-severe CEM (29%) was higher than those sharing the least-severe CEM (15%). Although the persistence of CEM on the networks varied, it generally survived for long periods of time; e.g., BitTorrent CEM had a survival rate near 100%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Empirical Correction for Differences in Chemical Exchange Rates in Hydrogen Exchange-Mass Spectrometry Measurements.

PubMed

Toth, Ronald T; Mills, Brittney J; Joshi, Sangeeta B; Esfandiary, Reza; Bishop, Steven M; Middaugh, C Russell; Volkin, David B; Weis, David D

2017-09-05

A barrier to the use of hydrogen exchange-mass spectrometry (HX-MS) in many contexts, especially analytical characterization of various protein therapeutic candidates, is that differences in temperature, pH, ionic strength, buffering agent, or other additives can alter chemical exchange rates, making HX data gathered under differing solution conditions difficult to compare. Here, we present data demonstrating that HX chemical exchange rates can be substantially altered not only by the well-established variables of temperature and pH but also by additives including arginine, guanidine, methionine, and thiocyanate. To compensate for these additive effects, we have developed an empirical method to correct the hydrogen-exchange data for these differences. First, differences in chemical exchange rates are measured by use of an unstructured reporter peptide, YPI. An empirical chemical exchange correction factor, determined by use of the HX data from the reporter peptide, is then applied to the HX measurements obtained from a protein of interest under different solution conditions. We demonstrate that the correction is experimentally sound through simulation and in a proof-of-concept experiment using unstructured peptides under slow-exchange conditions (pD 4.5 at ambient temperature). To illustrate its utility, we applied the correction to HX-MS excipient screening data collected for a pharmaceutically relevant IgG4 mAb being characterized to determine the effects of different formulations on backbone dynamics.

Densification and structural transitions in networks that grow by node copying

NASA Astrophysics Data System (ADS)

Bhat, U.; Krapivsky, P. L.; Lambiotte, R.; Redner, S.

2016-12-01

We introduce a growing network model, the copying model, in which a new node attaches to a randomly selected target node and, in addition, independently to each of the neighbors of the target with copying probability p . When p <1/2 , this algorithm generates sparse networks, in which the average node degree is finite. A power-law degree distribution also arises, with a nonuniversal exponent whose value is determined by a transcendental equation in p . In the sparse regime, the network is "normal," e.g., the relative fluctuations in the number of links are asymptotically negligible. For p ≥1/2 , the emergent networks are dense (the average degree increases with the number of nodes N ), and they exhibit intriguing structural behaviors. In particular, the N dependence of the number of m cliques (complete subgraphs of m nodes) undergoes m -1 transitions from normal to progressively more anomalous behavior at an m -dependent critical values of p . Different realizations of the network, which start from the same initial state, exhibit macroscopic fluctuations in the thermodynamic limit: absence of self-averaging. When linking to second neighbors of the target node can occur, the number of links asymptotically grows as N2 as N →∞ , so that the network is effectively complete as N →∞ .

Portable Parallel Programming for the Dynamic Load Balancing of Unstructured Grid Applications

NASA Technical Reports Server (NTRS)

Biswas, Rupak; Das, Sajal K.; Harvey, Daniel; Oliker, Leonid

1999-01-01

The ability to dynamically adapt an unstructured -rid (or mesh) is a powerful tool for solving computational problems with evolving physical features; however, an efficient parallel implementation is rather difficult, particularly from the view point of portability on various multiprocessor platforms We address this problem by developing PLUM, tin automatic anti architecture-independent framework for adaptive numerical computations in a message-passing environment. Portability is demonstrated by comparing performance on an SP2, an Origin2000, and a T3E, without any code modifications. We also present a general-purpose load balancer that utilizes symmetric broadcast networks (SBN) as the underlying communication pattern, with a goal to providing a global view of system loads across processors. Experiments on, an SP2 and an Origin2000 demonstrate the portability of our approach which achieves superb load balance at the cost of minimal extra overhead.

Large-scale P2P network based distributed virtual geographic environment (DVGE)

NASA Astrophysics Data System (ADS)

Tan, Xicheng; Yu, Liang; Bian, Fuling

2007-06-01

Virtual Geographic Environment has raised full concern as a kind of software information system that helps us understand and analyze the real geographic environment, and it has also expanded to application service system in distributed environment--distributed virtual geographic environment system (DVGE), and gets some achievements. However, limited by the factor of the mass data of VGE, the band width of network, as well as numerous requests and economic, etc. DVGE still faces some challenges and problems which directly cause the current DVGE could not provide the public with high-quality service under current network mode. The Rapid development of peer-to-peer network technology has offered new ideas of solutions to the current challenges and problems of DVGE. Peer-to-peer network technology is able to effectively release and search network resources so as to realize efficient share of information. Accordingly, this paper brings forth a research subject on Large-scale peer-to-peer network extension of DVGE as well as a deep study on network framework, routing mechanism, and DVGE data management on P2P network.

The leucine-rich amelogenin protein (LRAP) is primarily monomeric and unstructured in physiological solution

DOE PAGES

Tarasevich, Barbara J.; Philo, John S.; Maluf, Nasib Karl; ...

2014-10-25

Amelogenin proteins are critical to the formation of enamel in teeth and may have roles in promoting nucleation, controlling growth, and regulating microstructures of the intricately woven hydroxyapatite (HAP). Leucine-rich amelogenin protein (LRAP) is a 59-residue splice variant of amelogenin and contains the N- and C-terminal charged regions of the full-length protein thought to control crystal growth. Although the quaternary structure of full-length amelogenin in solution has been well studied and can consist of self-assemblies of monomers called nanospheres, the quaternary structure of LRAP is not as well studied. Here, analytical ultracentrifugation sedimentation velocity (SV) and small angle neutron scatteringmore » (SANS) were used to study the tertiary and quaternary structure of LRAP over a range of pH values, ionic strengths, and concentrations. SV has advantages over other techniques in accurately quantifying protein speciation in polydisperse solutions. We found that the monomer was the dominant species of phosphorylated LRAP (LRAP(+P)) over a range of solution conditions (pH 2.7 to 4.1, pH 4.5 to 8, 50 mmol/L( mM) to 200 mM NaCl, 0.065 to 2 mg/mL). The monomer was also the dominant species for unphosphorylated LRAP (LRAP(-P)) at pH 7.4 and LRAP(+P) in the presence of 2.5 mM calcium at pH 7.4. LRAP aggregated in a narrow pH range near the isoelectric point (pH 4.1). We conclude that LRAP does not form nanospheres under physiological solution conditions. Both SV and SANS showed that the LRAP monomer has a radius of ~2.0 nm and adopts an extended structure which solution NMR studies show is intrinsically disordered. This work provides new insights into the tertiary and quaternary structure of LRAP and further evidence that the monomeric species is an important functional form of amelogenins« less

A P2P Botnet detection scheme based on decision tree and adaptive multilayer neural networks.

PubMed

Alauthaman, Mohammad; Aslam, Nauman; Zhang, Li; Alasem, Rafe; Hossain, M A

2018-01-01

In recent years, Botnets have been adopted as a popular method to carry and spread many malicious codes on the Internet. These malicious codes pave the way to execute many fraudulent activities including spam mail, distributed denial-of-service attacks and click fraud. While many Botnets are set up using centralized communication architecture, the peer-to-peer (P2P) Botnets can adopt a decentralized architecture using an overlay network for exchanging command and control data making their detection even more difficult. This work presents a method of P2P Bot detection based on an adaptive multilayer feed-forward neural network in cooperation with decision trees. A classification and regression tree is applied as a feature selection technique to select relevant features. With these features, a multilayer feed-forward neural network training model is created using a resilient back-propagation learning algorithm. A comparison of feature set selection based on the decision tree, principal component analysis and the ReliefF algorithm indicated that the neural network model with features selection based on decision tree has a better identification accuracy along with lower rates of false positives. The usefulness of the proposed approach is demonstrated by conducting experiments on real network traffic datasets. In these experiments, an average detection rate of 99.08 % with false positive rate of 0.75 % was observed.

Synthesis and synchrotron X-ray characterization of two 2D Hoffman related compounds [Ni(p-Xylylenediamine)nNi(CN)4] and [Ni(p-tetrafluoroxylylenediamine)nNi(CN)4

NASA Astrophysics Data System (ADS)

Wong-Ng, W.; Culp, J. T.; Siderius, D. W.; Chen, Y. S.

2018-07-01

Synchrotron X-ray single crystal structure determination of two 2D Hofmann-related compounds, [Ni(p-Xylyenediamine)n-tetracyanonickelate] (abbreviated as Ni-pXdam) and [Ni(tetrafluoro-p-Xylyenediamine)n-tetracyanonickelate] (abbreviated as Ni-pXdamF4), have been conducted. Both the pXdam and pXdamF4 ligands contain two short chains of -CH2NH2 at the para-positions of a phenyl ring. These flexible chains link the 6-fold coordinated Ni2 sites throughout the network. In Ni-pXdam, the closed-2D network of [Ni-(CN-Ni1/4-)4]∞ is broken into 1D chains, leaving the C≡N groups at the trans-positions of the Ni(CN)4 moiety unbridged. The resulting 1D chains [(trans-)-NC-Ni(CN)2-CN-Ni-]∞ runs along the [010] direction of the unit cell. The pXdam ligands bridge in pair between the Ni atoms of the adjacent chains. The catenation structure of [Ni{(pXdam)}]∞ could be referred to as double -1D. In Ni-pXdamF4, the -CH2NH2 ligands connect the neighboring chains via the 6-fold Ni2 site. Surrounding the 4-fold Ni1 site, the two trans terminal C≡N groups were replaced by the Lewis base NH3 during the synthesis process, therefore preventing the propagation of the 2D net to form a 3D network. Computed pore volume of both compounds indicated that there is not sufficient space in the structure to accommodate gas molecules. In both compounds, hydrogen bonds were found, and solvent of crystallization was absent due to the limited free space in the structure.

Incentive Mechanism for P2P Content Sharing over Heterogenous Access Networks

NASA Astrophysics Data System (ADS)

Sato, Kenichiro; Hashimoto, Ryo; Yoshino, Makoto; Shinkuma, Ryoichi; Takahashi, Tatsuro

In peer-to-peer (P2P) content sharing, users can share their content by contributing their own resources to one another. However, since there is no incentive for contributing contents or resources to others, users may attempt to obtain content without any contribution. To motivate users to contribute their resources to the service, incentive-rewarding mechanisms have been proposed. On the other hand, emerging wireless technologies, such as IEEE 802.11 wireless local area networks, beyond third generation (B3G) cellular networks and mobile WiMAX, provide high-speed Internet access for wireless users. Using these high-speed wireless access, wireless users can use P2P services and share their content with other wireless users and with fixed users. However, this diversification of access networks makes it difficult to appropriately assign rewards to each user according to their contributions. This is because the cost necessary for contribution is different in different access networks. In this paper, we propose a novel incentive-rewarding mechanism called EMOTIVER that can assign rewards to users appropriately. The proposed mechanism uses an external evaluator and interactive learning agents. We also investigate a way of appropriately controlling rewards based on the system service's quality and managing policy.

FY 2013 Request for Proposals for the Pollution Prevention Information Network Grants Program

EPA Pesticide Factsheets

The Pollution Prevention Information Network (PPIN) grant program funds regional centers that serve both unique regional pollution prevention (P2) information needs and national audience needs for information on source reduction and related P2 practices.

Supporting Collaboration and Creativity Through Mobile P2P Computing

NASA Astrophysics Data System (ADS)

Wierzbicki, Adam; Datta, Anwitaman; Żaczek, Łukasz; Rzadca, Krzysztof

Among many potential applications of mobile P2P systems, collaboration applications are among the most prominent. Examples of applications such as Groove (although not intended for mobile networks), collaboration tools for disaster recovery (the WORKPAD project), and Skype's collaboration extensions, all demonstrate the potential of P2P collaborative applications. Yet, the development of such applications for mobile P2P systems is still difficult because of the lack of middleware.

An RNA internal loop acts as a hinge to facilitate ribozyme folding and catalysis.

PubMed Central

Szewczak, A A; Cech, T R

1997-01-01

RNA molecules commonly consist of helical regions separated by internal loops, and in many cases these internal loops have been found to assume stable structures. We have examined the function and dynamics of an internal loop, J5/5a, that joins the two halves of the P4-P6 domain of the Tetrahymena self-splicing group I intron. P4-P6 RNAs with mutations in the J5/5a region showed nondenaturing gel electrophoretic mobilities and levels of Fe(II)-EDTA cleavage protection intermediate between those of wild-type RNA and a mutant incapable of folding into the native P4-P6 tertiary structure. Mutants with the least structured J5/5a loops behaved the most like wild-type P4-P6, and required smaller amounts of Mg2+ to rescue folding. The activity of reconstituted introns containing mutant P4-P6 RNAs correlated similarly with the nature of the J5/5a mutation. Our results suggest that, in solution, the P4-P6 RNA is in a two-state equilibrium between folded and unfolded states. We conclude that this internal loop mainly acts as a flexible hinge, allowing the coaxially stacked helical regions on either side of it to interact via specific tertiary contacts. To a lesser extent, the specific bases within the loop contribute to folding. Furthermore, it is crucial that the junction remain unstructured in the unfolded state. These conclusions cannot be derived from a simple examination of the P4-P6 crystal structure (Cate JH et al., 1996, Science 273:1678-1685), showing once again that structure determination must be supplemented with mutational and thermodynamic analysis to provide a complete picture of a folded macromolecule. PMID:9257643

An interactional network of genes involved in chitin synthesis in Saccharomyces cerevisiae.

PubMed

Lesage, Guillaume; Shapiro, Jesse; Specht, Charles A; Sdicu, Anne-Marie; Ménard, Patrice; Hussein, Shamiza; Tong, Amy Hin Yan; Boone, Charles; Bussey, Howard

2005-02-16

In S. cerevisiae the beta-1,4-linked N-acetylglucosamine polymer, chitin, is synthesized by a family of 3 specialized but interacting chitin synthases encoded by CHS1, CHS2 and CHS3. Chs2p makes chitin in the primary septum, while Chs3p makes chitin in the lateral cell wall and in the bud neck, and can partially compensate for the lack of Chs2p. Chs3p requires a pathway of Bni4p, Chs4p, Chs5p, Chs6p and Chs7p for its localization and activity. Chs1p is thought to have a septum repair function after cell separation. To further explore interactions in the chitin synthase family and to find processes buffering chitin synthesis, we compiled a genetic interaction network of genes showing synthetic interactions with CHS1, CHS3 and genes involved in Chs3p localization and function and made a phenotypic analysis of their mutants. Using deletion mutants in CHS1, CHS3, CHS4, CHS5, CHS6, CHS7 and BNI4 in a synthetic genetic array analysis we assembled a network of 316 interactions among 163 genes. The interaction network with CHS3, CHS4, CHS5, CHS6, CHS7 or BNI4 forms a dense neighborhood, with many genes functioning in cell wall assembly or polarized secretion. Chitin levels were altered in 54 of the mutants in individually deleted genes, indicating a functional relationship between them and chitin synthesis. 32 of these mutants triggered the chitin stress response, with elevated chitin levels and a dependence on CHS3. A large fraction of the CHS1-interaction set was distinct from that of the CHS3 network, indicating broad roles for Chs1p in buffering both Chs2p function and more global cell wall robustness. Based on their interaction patterns and chitin levels we group interacting mutants into functional categories. Genes interacting with CHS3 are involved in the amelioration of cell wall defects and in septum or bud neck chitin synthesis, and we newly assign a number of genes to these functions. Our genetic analysis of genes not interacting with CHS3 indicate expanded roles for Chs4p, Chs5p and Chs6p in secretory protein trafficking and of Bni4p in bud neck organization.

Structural Transitions in Densifying Networks

NASA Astrophysics Data System (ADS)

Lambiotte, R.; Krapivsky, P. L.; Bhat, U.; Redner, S.

2016-11-01

We introduce a minimal generative model for densifying networks in which a new node attaches to a randomly selected target node and also to each of its neighbors with probability p . The networks that emerge from this copying mechanism are sparse for p <1/2 and dense (average degree increasing with number of nodes N ) for p ≥1/2 . The behavior in the dense regime is especially rich; for example, individual network realizations that are built by copying are disparate and not self-averaging. Further, there is an infinite sequence of structural anomalies at p =2/3 , 3/4 , 4/5 , etc., where the N dependences of the number of triangles (3-cliques), 4-cliques, undergo phase transitions. When linking to second neighbors of the target can occur, the probability that the resulting graph is complete—all nodes are connected—is nonzero as N →∞ .

Insight into a novel p53 single point mutation (G389E) by Molecular Dynamics Simulations.

PubMed

Pirolli, Davide; Carelli Alinovi, Cristiana; Capoluongo, Ettore; Satta, Maria Antonia; Concolino, Paola; Giardina, Bruno; De Rosa, Maria Cristina

2010-12-30

The majority of inactivating mutations of p53 reside in the central core DNA binding domain of the protein. In this computational study, we investigated the structural effects of a novel p53 mutation (G389E), identified in a patient with congenital adrenal hyperplasia, which is located within the extreme C-terminal domain (CTD) of p53, an unstructured, flexible region (residues 367-393) of major importance for the regulation of the protein. Based on the three-dimensional structure of a carboxyl-terminal peptide of p53 in complex with the S100B protein, which is involved in regulation of the tumor suppressor activity, a model of wild type (WT) and mutant extreme CTD was developed by molecular modeling and molecular dynamics simulation. It was found that the G389E amino acid replacement has negligible effects on free p53 in solution whereas it significantly affects the interactions of p53 with the S100B protein. The results suggest that the observed mutation may interfere with p53 transcription activation and provide useful information for site-directed mutagenesis experiments.

Complications of stent placement in patients with esophageal cancer: A systematic review and network meta-analysis

PubMed Central

Doosti-Irani, Amin; Mansournia, Mohammad Ali; Rahimi-Foroushani, Abbas; Haddad, Peiman

2017-01-01

Background Palliative treatments and stents are necessary for relieving dysphagia in patients with esophageal cancer. The aim of this study was to simultaneously compare available treatments in terms of complications. Methods Web of Science, Medline, Scopus, Cochrane Library and Embase were searched. Statistical heterogeneity was assessed using the Chi2 test and was quantified by I2. The results of this study were summarized in terms of Risk Ratio (RR). The random effects model was used to report the results. The rank probability for each treatment was calculated using the p-score. Results Out of 17855 references, 24 RCTs reported complications including treatment related death (TRD), bleeding, stent migration, aspiration, severe pain and fistula formation. In the ranking of treatments, thermal ablative therapy (p-score = 0.82), covered Evolution® stent (p-score = 0.70), brachytherapy (p-score = 0.72) and antireflux stent (p-score = 0.74) were better treatments in the network of TRD. Thermal ablative therapy (p-score = 0.86), the conventional stent (p-score = 0.62), covered Evolution® stent (p-score = 0.96) and brachytherapy (p-score = 0.82) were better treatments in the network of bleeding complications. Covered Evolution® (p-score = 0.78), uncovered (p-score = 0.88) and irradiation stents (p-score = 0.65) were better treatments in network of stent migration complications. In the network of severe pain, Conventional self-expandable nitinol alloy covered stent (p-score = 0.73), polyflex (p-score = 0.79), latex prosthesis (p-score = 0.96) and brachytherapy (p-score = 0.65) were better treatments. Conclusion According to our results, thermal ablative therapy, covered Evolution® stents, brachytherapy, and antireflux stents are associated with a lower risk of TRD. Moreover, thermal ablative therapy, conventional, covered Evolution® and brachytherapy had lower risks of bleeding. Overall, fewer complications were associated with covered Evolution® stent and brachytherapy. PMID:28968416

Integrity of helix 2-helix 3 domain of the PrP protein is not mandatory for prion replication.

PubMed

Salamat, Khalid; Moudjou, Mohammed; Chapuis, Jérôme; Herzog, Laetitia; Jaumain, Emilie; Béringue, Vincent; Rezaei, Human; Pastore, Annalisa; Laude, Hubert; Dron, Michel

2012-06-01

The process of prion conversion is not yet well understood at the molecular level. The regions critical for the conformational change of PrP remain mostly debated and the extent of sequence change acceptable for prion conversion is poorly documented. To achieve progress on these issues, we applied a reverse genetic approach using the Rov cell system. This allowed us to test the susceptibility of a number of insertion mutants to conversion into prion in the absence of wild-type PrP molecules. We were able to propagate several prions with 8 to 16 extra amino acids, including a polyglycine stretch and His or FLAG tags, inserted in the middle of the protease-resistant fragment. These results demonstrate the possibility to increase the length of the loop between helices H2 and H3 up to 4-fold, without preventing prion replication. They also indicate that this loop probably remains unstructured in PrP(Sc). We also showed that bona fide prions can be produced following insertion of octapeptides in the two C-terminal turns of H2. These insertions do not interfere with the overall fold of the H2-H3 domain indicating that the highly conserved sequence of the terminal part of H2 is not critical for the conversion. Altogether these data showed that the amplitude of modifications acceptable for prion conversion in the core of the globular domain of PrP is much greater than one might have assumed. These observations should help to refine structural models of PrP(Sc) and elucidate the conformational changes underlying prions generation.

Estimating temporal and spatial variation of ocean surface pCO2 in the North Pacific using a self-organizing map neural network technique

NASA Astrophysics Data System (ADS)

Nakaoka, S.; Telszewski, M.; Nojiri, Y.; Yasunaka, S.; Miyazaki, C.; Mukai, H.; Usui, N.

2013-09-01

This study uses a neural network technique to produce maps of the partial pressure of oceanic carbon dioxide (pCO2sea) in the North Pacific on a 0.25° latitude × 0.25° longitude grid from 2002 to 2008. The pCO2sea distribution was computed using a self-organizing map (SOM) originally utilized to map the pCO2sea in the North Atlantic. Four proxy parameters - sea surface temperature (SST), mixed layer depth, chlorophyll a concentration, and sea surface salinity (SSS) - are used during the training phase to enable the network to resolve the nonlinear relationships between the pCO2sea distribution and biogeochemistry of the basin. The observed pCO2sea data were obtained from an extensive dataset generated by the volunteer observation ship program operated by the National Institute for Environmental Studies (NIES). The reconstructed pCO2sea values agreed well with the pCO2sea measurements, with the root-mean-square error ranging from 17.6 μatm (for the NIES dataset used in the SOM) to 20.2 μatm (for independent dataset). We confirmed that the pCO2sea estimates could be improved by including SSS as one of the training parameters and by taking into account secular increases of pCO2sea that have tracked increases in atmospheric CO2. Estimated pCO2sea values accurately reproduced pCO2sea data at several time series locations in the North Pacific. The distributions of pCO2sea revealed by 7 yr averaged monthly pCO2sea maps were similar to Lamont-Doherty Earth Observatory pCO2sea climatology, allowing, however, for a more detailed analysis of biogeochemical conditions. The distributions of pCO2sea anomalies over the North Pacific during the winter clearly showed regional contrasts between El Niño and La Niña years related to changes of SST and vertical mixing.

Automated Extraction and Characterisation of Social Network Data from Unstructured Sources -- An Ontology-Based Approach

DTIC Science & Technology

2013-06-01

o provide da ocessed to e alyst can sea mation, it jus g the results e this, the SN iting for new  is  download  be modified  define  the  p xpression...ste y carving ou various steps n a notificati gies  from th logies of inte r  use  is  simi n refer to c s a generic    i.e.,  if  the  the quality a...on  the ust take  into ata  model a f the same d otype provid cument. The acts about th  in figure 4,  platform po always hold  xception  is  f fact

Toward a Rational Design of Bioactive Glasses with Optimal Structural Features: Composition–Structure Correlations Unveiled by Solid-State NMR and MD Simulations

PubMed Central

2013-01-01

The physiological responses of silicate-based bioactive glasses (BGs) are known to depend critically on both the P content (nP) of the glass and its silicate network connectivity (N̅BOSi). However, while the bioactivity generally displays a nonmonotonic dependence on nP itself, recent work suggest that it is merely the net orthophosphate content that directly links to the bioactivity. We exploit molecular dynamics (MD) simulations combined with 31P and 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy to explore the quantitative relationships between N̅BOSi, nP, and the silicate and phosphate speciations in a series of Na2O–CaO–SiO2–P2O5 glasses spanning 2.1 ≤ N̅BOSi ≤ 2.9 and variable P2O5 contents up to 6.0 mol %. The fractional population of the orthophosphate groups remains independent of nP at a fixed N̅BOSi-value, but is reduced slightly as N̅BOSi increases. Nevertheless, P remains predominantly as readily released orthophosphate ions, whose content may be altered essentially independently of the network connectivity, thereby offering a route to optimize the glass bioactivity. We discuss the observed composition-structure links in relation to known composition-bioactivity correlations, and define how Na2O–CaO–SiO2–P2O5 compositions exhibiting an optimal bioactivity can be designed by simultaneously altering three key parameters: the silicate network connectivity, the (ortho)phosphate content, and the nNa/nCa molar ratio. PMID:24364818

Fluid Analysis of Network Content Dissemination and Cloud Systems

DTIC Science & Technology

2017-03-06

orchestration of multiple transfers , within the constraints of the communication substrate. In unstructured or aggressive environments where wireless ad...previous AFOSR/SOARD project, concerns peer-to-peer dissemination in wireless ad-hoc networks. We focus on the necessary tradeoff between an efficient...use of the network substrate, and the necessary reciprocity between peers, aspects that may be in conflict in the wireless setting. Our results

Structural investigation of phosphate - bismuth glasses with vanadium

NASA Astrophysics Data System (ADS)

Stǎnescu, R.; Vedeanu, N.; Cozar, I. B.; Mǎgdaş, A.

2013-11-01

The xV2O5(1-dx)[0.5P2O5ṡ0.5Bi2O3] glass system with 0 ≤ x ≤ 50 mol% is investigated by IR and Raman spectroscopy. Both P2O5 and Bi2O3 oxides are known as network formers, but Bi2O3 is an unconventional one. At low content of vanadium oxide (x ≤ 5 mol%), both IR and Raman spectra are dominated by vibration bands characteristics to structural groups of phosphate and bismuthate lattices. Due to the network modifier role, vanadium oxide acts mainly on the Bi2O3 network allowing the phosphate groups to impose their characteristics absorption bands in spectra. These bands are strongly reduced for x ≥ 20 mol% due to the phosphate network depolymerization and the appearance of new vibrations characteristic to P-O-V, Bi-O-V and V-O-V groups showing the network former role of V2O5.

Academic English Socialization through Individual Networks of Practice

ERIC Educational Resources Information Center

Zappa-Hollman, Sandra; Duff, Patricia A.

2015-01-01

This article introduces the notion of individual network of practice (INoP) as a viable construct for analyzing academic (discourse) socialization in second language (L2) contexts. The authors provide an overview of social practice theories that have informed the development of INoP--community of practice (CoP; Lave & Wenger, 1991; Wenger,…

Engineering Amyloid-Like Assemblies from Unstructured Peptides via Site-Specific Lipid Conjugation

PubMed Central

López Deber, María Pilar; Hickman, David T.; Nand, Deepak; Baldus, Marc; Pfeifer, Andrea; Muhs, Andreas

2014-01-01

Aggregation of amyloid beta (Aβ) into oligomers and fibrils is believed to play an important role in the development of Alzheimer’s disease (AD). To gain further insight into the principles of aggregation, we have investigated the induction of β-sheet secondary conformation from disordered native peptide sequences through lipidation, in 1–2% hexafluoroisopropanol (HFIP) in phosphate buffered saline (PBS). Several parameters, such as type and number of lipid chains, peptide sequence, peptide length and net charge, were explored keeping the ratio peptide/HFIP constant. The resulting lipoconjugates were characterized by several physico-chemical techniques: Circular Dichroism (CD), Attenuated Total Reflection InfraRed (ATR-IR), Thioflavin T (ThT) fluorescence, Dynamic Light Scattering (DLS), solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy and Electron Microscopy (EM). Our data demonstrate the generation of β-sheet aggregates from numerous unstructured peptides under physiological pH, independent of the amino acid sequence. The amphiphilicity pattern and hydrophobicity of the scaffold were found to be key factors for their assembly into amyloid-like structures. PMID:25207975

Who Do You Know? Developing and Analyzing Entrepreneur Networks: Data Collection in the Tech Entrepreneurial Environment of Six African Cities

DTIC Science & Technology

2015-01-01

Prescribed by ANSI Std. Z39.18 4 1 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 January 2015...in detail in our 2 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 previous methodology paper. Based on...one of the leading universities in Sub-Saharan Africa. The student body is energetic and tech savvy. 3 | P a g e Network Science Center, West Point

A Holistic Redundancy- and Incentive-Based Framework to Improve Content Availability in Peer-to-Peer Networks

ERIC Educational Resources Information Center

Herrera-Ruiz, Octavio

2012-01-01

Peer-to-Peer (P2P) technology has emerged as an important alternative to the traditional client-server communication paradigm to build large-scale distributed systems. P2P enables the creation, dissemination and access to information at low cost and without the need of dedicated coordinating entities. However, existing P2P systems fail to provide…

Fault-Tolerant Algorithms for Connectivity Restoration in Wireless Sensor Networks.

PubMed

Zeng, Yali; Xu, Li; Chen, Zhide

2015-12-22

As wireless sensor network (WSN) is often deployed in a hostile environment, nodes in the networks are prone to large-scale failures, resulting in the network not working normally. In this case, an effective restoration scheme is needed to restore the faulty network timely. Most of existing restoration schemes consider more about the number of deployed nodes or fault tolerance alone, but fail to take into account the fact that network coverage and topology quality are also important to a network. To address this issue, we present two algorithms named Full 2-Connectivity Restoration Algorithm (F2CRA) and Partial 3-Connectivity Restoration Algorithm (P3CRA), which restore a faulty WSN in different aspects. F2CRA constructs the fan-shaped topology structure to reduce the number of deployed nodes, while P3CRA constructs the dual-ring topology structure to improve the fault tolerance of the network. F2CRA is suitable when the restoration cost is given the priority, and P3CRA is suitable when the network quality is considered first. Compared with other algorithms, these two algorithms ensure that the network has stronger fault-tolerant function, larger coverage area and better balanced load after the restoration.

Purinergic modulation of preBötzinger complex inspiratory rhythm in rodents: the interaction between ATP and adenosine

PubMed Central

Zwicker, J D; Rajani, V; Hahn, L B; Funk, G D

2011-01-01

Abstract ATP signalling in the CNS is mediated by a three-part system comprising the actions of ATP (and ADP) at P2 receptors (P2Rs), adenosine (ADO) at P1 receptors (P1Rs), and ectonucleotidases that degrade ATP into ADO. ATP excites preBötzinger complex (preBötC) inspiratory rhythm-generating networks where its release attenuates the hypoxic depression of breathing. Its metabolite, ADO, inhibits breathing through unknown mechanisms that may involve the preBötC. Our objective is to understand the dynamics of this signalling system and its influence on preBötC networks. We show that the preBötC of mouse and rat is sensitive to P2Y1 purinoceptor (P2Y1R) activation, responding with a >2-fold increase in frequency. Remarkably, the mouse preBötC is insensitive to ATP. Only after block of A1 ADORs is the ATP-evoked, P2Y1R-mediated frequency increase observed. This demonstrates that ATP is rapidly degraded to ADO, which activates inhibitory A1Rs, counteracting the P2Y1R-mediated excitation. ADO sensitivity of mouse preBötC was confirmed by a frequency decrease that was absent in rat. Differential ectonucleotidase activities are likely to contribute to the negligible ATP sensitivity of mouse preBötC. Real-time PCR analysis of ectonucleotidase isoforms in preBötC punches revealed TNAP (degrades ATP to ADO) or ENTPDase2 (favours production of excitatory ADP) as the primary constituent in mouse and rat, respectively. These data further establish the sensitivity of this vital network to P2Y1R-mediated excitation, emphasizing that individual components of the three-part signalling system dramatically alter network responses to ATP. Data also suggest therapeutic potential may derive from methods that alter the ATP–ADO balance to favour the excitatory actions of ATP. PMID:21788352

Computational and Experimental Unsteady Pressures for Alternate SLS Booster Nose Shapes

NASA Technical Reports Server (NTRS)

Braukmann, Gregory J.; Streett, Craig L.; Kleb, William L.; Alter, Stephen J.; Murphy, Kelly J.; Glass, Christopher E.

2015-01-01

Delayed Detached Eddy Simulation (DDES) predictions of the unsteady transonic flow about a Space Launch System (SLS) configuration were made with the Fully UNstructured Three-Dimensional (FUN3D) flow solver. The computational predictions were validated against results from a 2.5% model tested in the NASA Ames 11-Foot Transonic Unitary Plan Facility. The peak C(sub p,rms) value was under-predicted for the baseline, Mach 0.9 case, but the general trends of high C(sub p,rms) levels behind the forward attach hardware, reducing as one moves away both streamwise and circumferentially, were captured. Frequency of the peak power in power spectral density estimates was consistently under-predicted. Five alternate booster nose shapes were assessed, and several were shown to reduce the surface pressure fluctuations, both as predicted by the computations and verified by the wind tunnel results.

Neural correlates of processing sentences and compound words in Chinese

PubMed Central

Hung, Yi-Hui; Tzeng, Ovid; Wu, Denise H.

2017-01-01

Sentence reading involves multiple linguistic operations including processing of lexical and compositional semantics, and determining structural and grammatical relationships among words. Previous studies on Indo-European languages have associated left anterior temporal lobe (aTL) and left interior frontal gyrus (IFG) with reading sentences compared to reading unstructured word lists. To examine whether these brain regions are also involved in reading a typologically distinct language with limited morphosyntax and lack of agreement between sentential arguments, an FMRI study was conducted to compare passive reading of Chinese sentences, unstructured word lists and disconnected character lists that are created by only changing the order of an identical set of characters. Similar to previous findings from other languages, stronger activation was found in mainly left-lateralized anterior temporal regions (including aTL) for reading sentences compared to unstructured word and character lists. On the other hand, stronger activation was identified in left posterior temporal sulcus for reading unstructured words compared to unstructured characters. Furthermore, reading unstructured word lists compared to sentences evoked stronger activation in left IFG and left inferior parietal lobule. Consistent with the literature on Indo-European languages, the present results suggest that left anterior temporal regions subserve sentence-level integration, while left IFG supports restoration of sentence structure. In addition, left posterior temporal sulcus is associated with morphological compounding. Taken together, reading Chinese sentences engages a common network as reading other languages, with particular reliance on integration of semantic constituents. PMID:29194453

An exploration of the Facebook social networks of smokers and non-smokers.

PubMed

Fu, Luella; Jacobs, Megan A; Brookover, Jody; Valente, Thomas W; Cobb, Nathan K; Graham, Amanda L

2017-01-01

Social networks influence health behavior, including tobacco use and cessation. To date, little is known about whether and how the networks of online smokers and non-smokers may differ, or the potential implications of such differences with regards to intervention efforts. Understanding how social networks vary by smoking status could inform public health efforts to accelerate cessation or slow the adoption of tobacco use. These secondary analyses explore the structure of ego networks of both smokers and non-smokers collected as part of a randomized control trial conducted within Facebook. During the trial, a total of 14,010 individuals installed a Facebook smoking cessation app: 9,042 smokers who were randomized in the trial, an additional 2,881 smokers who did not meet full eligibility criteria, and 2,087 non-smokers. The ego network for all individuals was constructed out to second-degree connections. Four kinds of networks were constructed: friendship, family, photo, and group networks. From these networks we measured edges, isolates, density, mean betweenness, transitivity, and mean closeness. We also measured diameter, clustering, and modularity without ego and isolates. Logistic regressions were performed with smoking status as the response and network metrics as the primary independent variables and demographics and Facebook utilization metrics as covariates. The four networks had different characteristics, indicated by different multicollinearity issues and by logistic regression output. Among Friendship networks, the odds of smoking were higher in networks with lower betweenness (p = 0.00), lower transitivity (p = 0.00), and larger diameter (p = 0.00). Among Family networks, the odds of smoking were higher in networks with more vertices (p = .01), less transitivity (p = .04), and fewer isolates (p = .01). Among Photo networks, none of the network metrics were predictive of smoking status. Among Group networks, the odds of smoking were higher when diameter was smaller (p = .04). Together, these findings suggested that compared to non-smokers, smokers in this sample had less connected, more dispersed Facebook Friendship networks; larger but more fractured Family networks with fewer isolates; more compact Group networks; and Photo networks that were similar in network structure to those of non-smokers. This study illustrates the importance of examining structural differences in online social networks as a critical component for network-based interventions and lays the foundation for future research that examines the ways that social networks differ based on individual health behavior. Interventions that seek to target the behavior of individuals in the context of their social environment would be well served to understand social network structures of participants.

An exploration of the Facebook social networks of smokers and non-smokers

PubMed Central

2017-01-01

Background Social networks influence health behavior, including tobacco use and cessation. To date, little is known about whether and how the networks of online smokers and non-smokers may differ, or the potential implications of such differences with regards to intervention efforts. Understanding how social networks vary by smoking status could inform public health efforts to accelerate cessation or slow the adoption of tobacco use. Objectives These secondary analyses explore the structure of ego networks of both smokers and non-smokers collected as part of a randomized control trial conducted within Facebook. Methods During the trial, a total of 14,010 individuals installed a Facebook smoking cessation app: 9,042 smokers who were randomized in the trial, an additional 2,881 smokers who did not meet full eligibility criteria, and 2,087 non-smokers. The ego network for all individuals was constructed out to second-degree connections. Four kinds of networks were constructed: friendship, family, photo, and group networks. From these networks we measured edges, isolates, density, mean betweenness, transitivity, and mean closeness. We also measured diameter, clustering, and modularity without ego and isolates. Logistic regressions were performed with smoking status as the response and network metrics as the primary independent variables and demographics and Facebook utilization metrics as covariates. Results The four networks had different characteristics, indicated by different multicollinearity issues and by logistic regression output. Among Friendship networks, the odds of smoking were higher in networks with lower betweenness (p = 0.00), lower transitivity (p = 0.00), and larger diameter (p = 0.00). Among Family networks, the odds of smoking were higher in networks with more vertices (p = .01), less transitivity (p = .04), and fewer isolates (p = .01). Among Photo networks, none of the network metrics were predictive of smoking status. Among Group networks, the odds of smoking were higher when diameter was smaller (p = .04). Together, these findings suggested that compared to non-smokers, smokers in this sample had less connected, more dispersed Facebook Friendship networks; larger but more fractured Family networks with fewer isolates; more compact Group networks; and Photo networks that were similar in network structure to those of non-smokers. Conclusions This study illustrates the importance of examining structural differences in online social networks as a critical component for network-based interventions and lays the foundation for future research that examines the ways that social networks differ based on individual health behavior. Interventions that seek to target the behavior of individuals in the context of their social environment would be well served to understand social network structures of participants. PMID:29095958

Supporting Seamless Mobility for P2P Live Streaming

PubMed Central

Kim, Eunsam; Kim, Sangjin; Lee, Choonhwa

2014-01-01

With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme. PMID:24977171

Formation of nanoscale networks: selectively swelling amphiphilic block copolymers with CO2-expanded liquids

NASA Astrophysics Data System (ADS)

Gong, Jianliang; Zhang, Aijuan; Bai, Hua; Zhang, Qingkun; Du, Can; Li, Lei; Hong, Yanzhen; Li, Jun

2013-01-01

Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), with the CO2-expanded liquid (CXL), CO2-methanol. The phase behavior of the CO2-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO2, forming homogeneous CXL under the experimental conditions. When treated with the CO2-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a temperature range of 45-60 °C. The formation mechanism of the network, involving plasticization of PS and selective swelling of P4VP, was proposed. Because the diblock copolymer diffusion process is controlled by the activated hopping of individual block copolymer chains with the thermodynamic barrier for moving PVP segments from one to another, the formation of the network structures is achieved in a short time scale and shows ``thermodynamically restricted'' character. Furthermore, the resulting polymer networks were employed as templates, for the preparation of polypyrrole networks, by an electrochemical polymerization process. The prepared porous polypyrrole film was used to fabricate a chemoresistor-type gas sensor which showed high sensitivity towards ammonia.Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), with the CO2-expanded liquid (CXL), CO2-methanol. The phase behavior of the CO2-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO2, forming homogeneous CXL under the experimental conditions. When treated with the CO2-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a temperature range of 45-60 °C. The formation mechanism of the network, involving plasticization of PS and selective swelling of P4VP, was proposed. Because the diblock copolymer diffusion process is controlled by the activated hopping of individual block copolymer chains with the thermodynamic barrier for moving PVP segments from one to another, the formation of the network structures is achieved in a short time scale and shows ``thermodynamically restricted'' character. Furthermore, the resulting polymer networks were employed as templates, for the preparation of polypyrrole networks, by an electrochemical polymerization process. The prepared porous polypyrrole film was used to fabricate a chemoresistor-type gas sensor which showed high sensitivity towards ammonia. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33188h

Octarepeat region flexibility impacts prion function, endoproteolysis and disease manifestation

PubMed Central

Lau, Agnes; McDonald, Alex; Daude, Nathalie; Mays, Charles E; Walter, Eric D; Aglietti, Robin; Mercer, Robert CC; Wohlgemuth, Serene; van der Merwe, Jacques; Yang, Jing; Gapeshina, Hristina; Kim, Chae; Grams, Jennifer; Shi, Beipei; Wille, Holger; Balachandran, Aru; Schmitt-Ulms, Gerold; Safar, Jiri G; Millhauser, Glenn L; Westaway, David

2015-01-01

The cellular prion protein (PrPC) comprises a natively unstructured N-terminal domain, including a metal-binding octarepeat region (OR) and a linker, followed by a C-terminal domain that misfolds to form PrPSc in Creutzfeldt-Jakob disease. PrPC β-endoproteolysis to the C2 fragment allows PrPSc formation, while α-endoproteolysis blocks production. To examine the OR, we used structure-directed design to make novel alleles, ‘S1’ and ‘S3’, locking this region in extended or compact conformations, respectively. S1 and S3 PrP resembled WT PrP in supporting peripheral nerve myelination. Prion-infected S1 and S3 transgenic mice both accumulated similar low levels of PrPSc and infectious prion particles, but differed in their clinical presentation. Unexpectedly, S3 PrP overproduced C2 fragment in the brain by a mechanism distinct from metal-catalysed hydrolysis reported previously. OR flexibility is concluded to impact diverse biological endpoints; it is a salient variable in infectious disease paradigms and modulates how the levels of PrPSc and infectivity can either uncouple or engage to drive the onset of clinical disease. PMID:25661904

P4-ATPase Requirement for AP-1/Clathrin Function in Protein Transport from the trans-Golgi Network and Early Endosomes

PubMed Central

Liu, Ke; Surendhran, Kavitha; Nothwehr, Steven F.

2008-01-01

Drs2p is a resident type 4 P-type ATPase (P4-ATPase) and potential phospholipid translocase of the trans-Golgi network (TGN) where it has been implicated in clathrin function. However, precise protein transport pathways requiring Drs2p and how it contributes to clathrin-coated vesicle budding remain unclear. Here we show a functional codependence between Drs2p and the AP-1 clathrin adaptor in protein sorting at the TGN and early endosomes of Saccharomyces cerevisiae. Genetic criteria indicate that Drs2p and AP-1 operate in the same pathway and that AP-1 requires Drs2p for function. In addition, we show that loss of AP-1 markedly increases Drs2p trafficking to the plasma membrane, but does not perturb retrieval of Drs2p from the early endosome back to the TGN. Thus AP-1 is required at the TGN to sort Drs2p out of the exocytic pathway, presumably for delivery to the early endosome. Moreover, a conditional allele that inactivates Drs2p phospholipid translocase (flippase) activity disrupts its own transport in this AP-1 pathway. Drs2p physically interacts with AP-1; however, AP-1 and clathrin are both recruited normally to the TGN in drs2Δ cells. These results imply that Drs2p acts independently of coat recruitment to facilitate AP-1/clathrin-coated vesicle budding from the TGN. PMID:18508916

Cooperative binding modes of Cu(II) in prion protein

NASA Astrophysics Data System (ADS)

Hodak, Miroslav; Chisnell, Robin; Lu, Wenchang; Bernholc, Jerry

2007-03-01

The misfolding of the prion protein, PrP, is responsible for a group of neurodegenerative diseases including mad cow disease and Creutzfeldt-Jakob disease. It is known that the PrP can efficiently bind copper ions; four high-affinity binding sites located in the octarepeat region of PrP are now well known. Recent experiments suggest that at low copper concentrations new binding modes, in which one copper ion is shared between two or more binding sites, are possible. Using our hybrid Thomas-Fermi/DFT computational scheme, which is well suited for simulations of biomolecules in solution, we investigate the geometries and energetics of two, three and four binding sites cooperatively binding one copper ion. These geometries are then used as inputs for classical molecular dynamics simulations. We find that copper binding affects the secondary structure of the PrP and that it stabilizes the unstructured (unfolded) part of the protein.

Integrating P3 Data Into P2 Analyses: What is the Added Value

Treesearch

James R. Steinman

2001-01-01

The Forest Inventory and Analysis and Forest Health Monitoring Programs of the USDA Forest Service are integrating field procedures for measuring their networks of plots throughout the United States. These plots are now referred to as Phase 2 (P2) and Phase 3 (P3) plots, respectively, and 1 out of every 16 P2 plots will also be a P3 plot. Mensurational methods will be...

An interactional network of genes involved in chitin synthesis in Saccharomyces cerevisiae

PubMed Central

Lesage, Guillaume; Shapiro, Jesse; Specht, Charles A; Sdicu, Anne-Marie; Ménard, Patrice; Hussein, Shamiza; Tong, Amy Hin Yan; Boone, Charles; Bussey, Howard

2005-01-01

Background In S. cerevisiae the β-1,4-linked N-acetylglucosamine polymer, chitin, is synthesized by a family of 3 specialized but interacting chitin synthases encoded by CHS1, CHS2 and CHS3. Chs2p makes chitin in the primary septum, while Chs3p makes chitin in the lateral cell wall and in the bud neck, and can partially compensate for the lack of Chs2p. Chs3p requires a pathway of Bni4p, Chs4p, Chs5p, Chs6p and Chs7p for its localization and activity. Chs1p is thought to have a septum repair function after cell separation. To further explore interactions in the chitin synthase family and to find processes buffering chitin synthesis, we compiled a genetic interaction network of genes showing synthetic interactions with CHS1, CHS3 and genes involved in Chs3p localization and function and made a phenotypic analysis of their mutants. Results Using deletion mutants in CHS1, CHS3, CHS4, CHS5, CHS6, CHS7 and BNI4 in a synthetic genetic array analysis we assembled a network of 316 interactions among 163 genes. The interaction network with CHS3, CHS4, CHS5, CHS6, CHS7 or BNI4 forms a dense neighborhood, with many genes functioning in cell wall assembly or polarized secretion. Chitin levels were altered in 54 of the mutants in individually deleted genes, indicating a functional relationship between them and chitin synthesis. 32 of these mutants triggered the chitin stress response, with elevated chitin levels and a dependence on CHS3. A large fraction of the CHS1-interaction set was distinct from that of the CHS3 network, indicating broad roles for Chs1p in buffering both Chs2p function and more global cell wall robustness. Conclusion Based on their interaction patterns and chitin levels we group interacting mutants into functional categories. Genes interacting with CHS3 are involved in the amelioration of cell wall defects and in septum or bud neck chitin synthesis, and we newly assign a number of genes to these functions. Our genetic analysis of genes not interacting with CHS3 indicate expanded roles for Chs4p, Chs5p and Chs6p in secretory protein trafficking and of Bni4p in bud neck organization. PMID:15715908

Redundancy Maintenance and Garbage Collection Strategies in Peer-to-Peer Storage Systems

NASA Astrophysics Data System (ADS)

Liu, Xin; Datta, Anwitaman

Maintaining redundancy in P2P storage systems is essential for reliability guarantees. Numerous P2P storage system maintenance algorithms have been proposed in the last years, each supposedly improving upon the previous approaches. We perform a systematic comparative study of the various strategies taking also into account the influence of different garbage collection mechanisms, an issue not studied so far. Our experiments show that while some strategies generally perform better than some others, there is no universally best strategy, and their relative superiority depends on various other design choices as well as the specific evaluation criterion. Our results can be used by P2P storage systems designers to make prudent design decisions, and our exploration of the various evaluation metrics also provides a more comprehensive framework to compare algorithms for P2P storage systems. While there are numerous network simulators specifically developed even to simulate peer-to-peer networks, there existed no P2P storage simulators - a byproduct of this work is a generic modular P2P storage system simulator which we provide as open-source. Different redundancy, maintenance, placement, garbage-collection policies, churn scenarios can be easily integrated to the simulator to try out new schemes in future, and provides a common framework to compare (future) p2p storage systems designs - something which has not been possible so far.

Robust Multi-Agent Sensor Network Systems

DTIC Science & Technology

2012-05-08

Localization on the Sphere, International Journal of Intelligent Defence Support System, Vol. 4, no. 4, 2011, pp. 328-350. Quality of Network... Quality of Service (QoS). The following standards are included in the IEEE 1609 standard family: IEEE P1609.0, IEEE P1609.1, IEEE P1609.2, IEEE P1609.3...protocols to support safety services in ITS,” in IEEE International Conference on Emerging Technologies and Factory Au- tomation (ETFA), 2008, pp. 1189

Adaptive Neural Networks Decentralized FTC Design for Nonstrict-Feedback Nonlinear Interconnected Large-Scale Systems Against Actuator Faults.

PubMed

Li, Yongming; Tong, Shaocheng

The problem of active fault-tolerant control (FTC) is investigated for the large-scale nonlinear systems in nonstrict-feedback form. The nonstrict-feedback nonlinear systems considered in this paper consist of unstructured uncertainties, unmeasured states, unknown interconnected terms, and actuator faults (e.g., bias fault and gain fault). A state observer is designed to solve the unmeasurable state problem. Neural networks (NNs) are used to identify the unknown lumped nonlinear functions so that the problems of unstructured uncertainties and unknown interconnected terms can be solved. By combining the adaptive backstepping design principle with the combination Nussbaum gain function property, a novel NN adaptive output-feedback FTC approach is developed. The proposed FTC controller can guarantee that all signals in all subsystems are bounded, and the tracking errors for each subsystem converge to a small neighborhood of zero. Finally, numerical results of practical examples are presented to further demonstrate the effectiveness of the proposed control strategy.The problem of active fault-tolerant control (FTC) is investigated for the large-scale nonlinear systems in nonstrict-feedback form. The nonstrict-feedback nonlinear systems considered in this paper consist of unstructured uncertainties, unmeasured states, unknown interconnected terms, and actuator faults (e.g., bias fault and gain fault). A state observer is designed to solve the unmeasurable state problem. Neural networks (NNs) are used to identify the unknown lumped nonlinear functions so that the problems of unstructured uncertainties and unknown interconnected terms can be solved. By combining the adaptive backstepping design principle with the combination Nussbaum gain function property, a novel NN adaptive output-feedback FTC approach is developed. The proposed FTC controller can guarantee that all signals in all subsystems are bounded, and the tracking errors for each subsystem converge to a small neighborhood of zero. Finally, numerical results of practical examples are presented to further demonstrate the effectiveness of the proposed control strategy.

Conformation-Specific Infrared and Ultraviolet Spectroscopy of Cold [YAPAA+H]^{+} and [YGPAA+H]^{+} Ions: a Stereochemical "twist" on the β-HAIRPIN Turn

NASA Astrophysics Data System (ADS)

DeBlase, Andrew F.; Harrilal, Christopher P.; Lawler, John T.; Burke, Nicole L.; McLuckey, Scott A.; Zwier, Timothy S.

2017-06-01

Incorporation of the unnatural D-proline (^{D}P) stereoisomer into a polypeptide sequence is a typical strategy to encourage formation of β-hairpin loops because natural sequences are often unstructured in solution. Using conformation-specific IR and UV spectroscopy of cold (10 K) gas-phase ions, we probe the inherent conformational preferences of the ^{D}P and ^{L}P diastereomers in the protonated peptide [YAPAA+H]^{+}, where only intramolecular interactions are possible. Consistent with the solution phase studies, one of the conformers of [YADPAA+H]^{+} is folded into a charge-stabilized β-hairpin turn. However, a second predominant conformer family containing two sequential γ-turns is also identified, with similar energetic stability. A single conformational isomer of the ^{L}P diastereomer, [YALPAA+H]^{+}, is found and assigned to a structure that is not the anticipated "mirror image" β-turn. Instead, the ^{L}P stereo center promotes a cis alanine-proline amide bond. The assigned structures contain clues that the preference of the ^{D}P diastereomer to support a trans-amide bond and the proclivity of ^{L}P for a cis-amide bond is sterically driven and can be reversed by substituting glycine for alanine in position 2, forming [YGLPAA+H]^{+}. These results provide a basis for understanding the residue-specific and stereo-specific alterations in the potential energy surface that underlie these changing preferences, providing insights to the origin of β-hairpin formation.

Regenerative Simulation of Response Times in Networks of Queues.

DTIC Science & Technology

1979-11-01

i jobs at center 1. Nov consider the network of queues in Figure 2.2, formulated (Lewis and Shedler ( 1971 )) as a model of system overhead in...7.2 leading to point estimates and confidence intervals for the quantity r(f) are that the pairs of random variables {( V(fHk) : kall (9.2.3) are...189 Next we show that P’=P. Since P ’m"CIP for all i, we can use the Skorohod representation theorem (see Skorohod (1956) or Billingsley ( 1971 )) to

A peer-to-peer music sharing system based on query-by-humming

NASA Astrophysics Data System (ADS)

Wang, Jianrong; Chang, Xinglong; Zhao, Zheng; Zhang, Yebin; Shi, Qingwei

2007-09-01

Today, the main traffic in peer-to-peer (P2P) network is still multimedia files including large numbers of music files. The study of Music Information Retrieval (MIR) brings out many encouraging achievements in music search area. Nevertheless, the research of music search based on MIR in P2P network is still insufficient. Query by Humming (QBH) is one MIR technology studied for years. In this paper, we present a server based P2P music sharing system which is based on QBH and integrated with a Hierarchical Index Structure (HIS) to enhance the relation between surface data and potential information. HIS automatically evolving depends on the music related items carried by each peer such as midi files, lyrics and so forth. Instead of adding large amount of redundancy, the system generates a bit of index for multiple search input which improves the traditional keyword-based text search mode largely. When network bandwidth, speed, etc. are no longer a bottleneck of internet serve, the accessibility and accuracy of information provided by internet are being more concerned by end users.

Efficacy of Peer Networks to Increase Social Connections among High School Students with and without Autism Spectrum Disorder

ERIC Educational Resources Information Center

Hochman, Julia M.; Carter, Erik W.; Bottema-Beutel, Kristen; Harvey, Michelle N.; Gustafson, Jenny R.

2015-01-01

Although peer interaction takes on increased salience during adolescence, such social connections remain elusive for many high school students with autism spectrum disorder (ASD). This social isolation can be particularly prevalent within unstructured school contexts.In this study, we examined the effects of a lunchtime peer network intervention…

Efficacy of Peer Networks to Increase Social Connections among High School Students with and without Autism Spectrum Disorder

ERIC Educational Resources Information Center

Hochman, Julia M.; Carter, Erik W.; Bottema-Beutel, Kristen; Harvey, Michelle N.; Gustafson, Jenny R.

2015-01-01

Although peer interaction takes on increased salience during adolescence, such social connections remain elusive for many high school students with autism spectrum disorder (ASD). This social isolation can be particularly prevalent within unstructured school contexts. In this study, we examined the effects of a lunchtime peer network intervention…

Non-overlapped P- and S-wave Poynting vectors and their solution by the grid method

NASA Astrophysics Data System (ADS)

Lu, Yongming; Liu, Qiancheng

2018-06-01

The Poynting vector represents the local directional energy flux density of seismic waves in geophysics. It is widely used in elastic reverse time migration to analyze source illumination, suppress low-wavenumber noise, correct for image polarity and extract angle-domain common-image gathers. However, the P- and S-waves are mixed together during wavefield propagation so that the P and S energy fluxes are not clean everywhere, especially at the overlapped points. In this paper, we use a modified elastic-wave equation in which the P and S vector wavefields are naturally separated. Then, we develop an efficient method to evaluate the separable P and S Poynting vectors, respectively, based on the view that the group velocity and phase velocity have the same direction in isotropic elastic media. We furthermore formulate our method using an unstructured mesh-based modeling method named the grid method. Finally, we verify our method using two numerical examples.

Transcription factor FOXA2-centered transcriptional regulation network in non-small cell lung cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Sang-Min; An, Joo-Hee; Kim, Chul-Hong

2015-08-07

Lung cancer is the leading cause of cancer-mediated death. Although various therapeutic approaches are used for lung cancer treatment, these mainly target the tumor suppressor p53 transcription factor, which is involved in apoptosis and cell cycle arrest. However, p53-targeted therapies have limited application in lung cancer, since p53 is found to be mutated in more than half of lung cancers. In this study, we propose tumor suppressor FOXA2 as an alternative target protein for therapies against lung cancer and reveal a possible FOXA2-centered transcriptional regulation network by identifying new target genes and binding partners of FOXA2 by using various screeningmore » techniques. The genes encoding Glu/Asp-rich carboxy-terminal domain 2 (CITED2), nuclear receptor subfamily 0, group B, member 2 (NR0B2), cell adhesion molecule 1 (CADM1) and BCL2-associated X protein (BAX) were identified as putative target genes of FOXA2. Additionally, the proteins including highly similar to heat shock protein HSP 90-beta (HSP90A), heat shock 70 kDa protein 1A variant (HSPA1A), histone deacetylase 1 (HDAC1) and HDAC3 were identified as novel interacting partners of FOXA2. Moreover, we showed that FOXA2-dependent promoter activation of BAX and p21 genes is significantly reduced via physical interactions between the identified binding partners and FOXA2. These results provide opportunities to understand the FOXA2-centered transcriptional regulation network and novel therapeutic targets to modulate this network in p53-deficient lung cancer. - Highlights: • Identification of new target genes of FOXA2. • Identifications of novel interaction proteins of FOXA2. • Construction of FOXA2-centered transcriptional regulatory network in non-small cell lung cancer.« less

Indium tin oxide nanopillar electrodes in polymer/fullerene solar cells.

PubMed

Rider, David A; Tucker, Ryan T; Worfolk, Brian J; Krause, Kathleen M; Lalany, Abeed; Brett, Michael J; Buriak, Jillian M; Harris, Kenneth D

2011-02-25

Using high surface area nanostructured electrodes in organic photovoltaic (OPV) devices is a route to enhanced power conversion efficiency. In this paper, indium tin oxide (ITO) and hybrid ITO/SiO(2) nanopillars are employed as three-dimensional high surface area transparent electrodes in OPVs. The nanopillar arrays are fabricated via glancing angle deposition (GLAD) and electrochemically modified with nanofibrous PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(p-styrenesulfonate)). The structures are found to have increased surface area as characterized by porosimetry. When applied as anodes in polymer/fullerene OPVs (architecture: commercial ITO/GLAD ITO/PEDOT:PSS/P3HT:PCBM/Al, where P3HT is 2,5-diyl-poly(3-hexylthiophene) and PCBM is [6,6]-phenyl-C(61)-butyric acid methyl ester), the air-processed solar cells incorporating high surface area, PEDOT:PSS-modified ITO nanoelectrode arrays operate with improved performance relative to devices processed identically on unstructured, commercial ITO substrates. The resulting power conversion efficiency is 2.2% which is a third greater than for devices prepared on commercial ITO. To further refine the structure, insulating SiO(2) caps are added above the GLAD ITO nanopillars to produce a hybrid ITO/SiO(2) nanoelectrode. OPV devices based on this system show reduced electrical shorting and series resistance, and as a consequence, a further improved power conversion efficiency of 2.5% is recorded.

DARPA Ensemble-Based Modeling Large Graphs & Applications to Social Networks

DTIC Science & Technology

2015-07-29

Fortunato, and D. Krioukov. How random are complex networks. Nature Communications , submitted (2015). http://arxiv.org/abs/1505.07503 [p2] I. Miklos...enterprise communication networks, PLOS One, 10(3), e0119446 (2015). http://arxiv.org/abs/1404.3708v3 [p21] A. Nyberg, T. Gross, and K.E. Bassler...using a radiation model based on temporal ranges. Nature Communications , 5, 5347 (2014) | http://arxiv.org/abs/1410.4849 [p28] L.A. Székely, H. Wang

Crystal structures of dye-decolorizing peroxidase with ascorbic acid and 2,6-dimethoxyphenol.

PubMed

Yoshida, Toru; Tsuge, Hideaki; Hisabori, Toru; Sugano, Yasushi

2012-12-14

The structure of dye-decolorizing peroxidase (DyP)-type peroxidase differs from that of other peroxidase families, indicating that DyP-type peroxidases have a different reaction mechanism. We have determined the crystal structures of DyP with ascorbic acid and 2,6-dimethoxyphenol at 1.5 and 1.4Å, respectively. The common binding site for both substrates was located at the entrance of the second cavity leading from the DyP molecular surface to heme. This resulted in a hydrogen bond network connection between each substrate and the heme distal side. This network consisted of water molecules occupying the second cavity, heme 6-propionate, Arg329, and Asn313. This network is consistent with the proton transfer pathway from substrate to DyP. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

High order spectral volume and spectral difference methods on unstructured grids

NASA Astrophysics Data System (ADS)

Kannan, Ravishekar

The spectral volume (SV) and the spectral difference (SD) methods were developed by Wang and Liu and their collaborators for conservation laws on unstructured grids. They were introduced to achieve high-order accuracy in an efficient manner. Recently, these methods were extended to three-dimensional systems and to the Navier Stokes equations. The simplicity and robustness of these methods have made them competitive against other higher order methods such as the discontinuous Galerkin and residual distribution methods. Although explicit TVD Runge-Kutta schemes for the temporal advancement are easy to implement, they suffer from small time step limited by the Courant-Friedrichs-Lewy (CFL) condition. When the polynomial order is high or when the grid is stretched due to complex geometries or boundary layers, the convergence rate of explicit schemes slows down rapidly. Solution strategies to remedy this problem include implicit methods and multigrid methods. A novel implicit lower-upper symmetric Gauss-Seidel (LU-SGS) relaxation method is employed as an iterative smoother. It is compared to the explicit TVD Runge-Kutta smoothers. For some p-multigrid calculations, combining implicit and explicit smoothers for different p-levels is also studied. The multigrid method considered is nonlinear and uses Full Approximation Scheme (FAS). An overall speed-up factor of up to 150 is obtained using a three-level p-multigrid LU-SGS approach in comparison with the single level explicit method for the Euler equations for the 3rd order SD method. A study of viscous flux formulations was carried out for the SV method. Three formulations were used to discretize the viscous fluxes: local discontinuous Galerkin (LDG), a penalty method and the 2nd method of Bassi and Rebay. Fourier analysis revealed some interesting advantages for the penalty method. These were implemented in the Navier Stokes solver. An implicit and p-multigrid method was also implemented for the above. An overall speed-up factor of up to 1500 is obtained using a three-level p-multigrid LU-SGS approach in comparison with the single level explicit method for the Navier-Stokes equations. The SV method was also extended to turbulent flows. The RANS based SA model was used to close the Reynolds stresses. The numerical results are very promising and indicate that the approaches have great potentials for 3D flow problems.

Critical components of the pluripotency network are targets for the p300/CBP interacting protein (p/CIP) in embryonic stem cells.

PubMed

Chitilian, J M; Thillainadesan, G; Manias, J L; Chang, W Y; Walker, E; Isovic, M; Stanford, W L; Torchia, J

2014-01-01

p/CIP, also known as steroid receptor coactivator 3 (SRC-3)/Nuclear Receptor Coactivator 3 (NCoA3), is a transcriptional coactivator that binds liganded nuclear hormone receptors, as well as other transcription factors, and facilitates transcription through direct recruitment of accessory factors. We have found that p/CIP is highly expressed in undifferentiated mouse embryonic stem cells (mESCs) and is downregulated during differentiation. siRNA-mediated knockdown of p/CIP decreased transcript levels of Nanog, but not Oct4 or Sox2. Microarray expression analysis showed that Klf4, Tbx3, and Dax-1 are significantly downregulated in mESCs when p/CIP is knocked down. Subsequent chromatin immunoprecipitation (ChIP) analysis demonstrated that Tbx3, Klf4, and Dax-1 are direct transcriptional targets of p/CIP. Using the piggyBac transposition system, a mouse ESC line that expresses Flag-p/CIP in a doxycycline-dependent manner was generated. p/CIP overexpression increased the level of target genes and promoted the formation of undifferentiated colonies. Collectively, these results indicate that p/CIP contributes to the maintenance of ESC pluripotency through direct regulation of essential pluripotency genes. To better understand the mechanism by which p/CIP functions in ESC pluripotency, we integrated our ChIP and transcriptome data with published protein-protein interaction and promoter occupancy data to draft a p/CIP gene regulatory network. The p/CIP gene regulatory network identifies various feed-forward modules including one in which p/CIP activates members of the extended pluripotency network, demonstrating that p/CIP is a component of this extended network. © AlphaMed Press.

A Cyclin T1 point mutation that abolishes positive transcription elongation factor (P-TEFb) binding to Hexim1 and HIV tat

PubMed Central

2014-01-01

Background The positive transcription elongation factor b (P-TEFb) plays an essential role in activating HIV genome transcription. It is recruited to the HIV LTR promoter through an interaction between the Tat viral protein and its Cyclin T1 subunit. P-TEFb activity is inhibited by direct binding of its subunit Cyclin T (1 or 2) with Hexim (1 or 2), a cellular protein, bound to the 7SK small nuclear RNA. Hexim1 competes with Tat for P-TEFb binding. Results Mutations that impair human Cyclin T1/Hexim1 interaction were searched using systematic mutagenesis of these proteins coupled with a yeast two-hybrid screen for loss of protein interaction. Evolutionary conserved Hexim1 residues belonging to an unstructured peptide located N-terminal of the dimerization domain, were found to be critical for P-TEFb binding. Random mutagenesis of the N-terminal region of Cyclin T1 provided identification of single amino-acid mutations that impair Hexim1 binding in human cells. Furthermore, conservation of critical residues supported the existence of a functional Hexim1 homologue in nematodes. Conclusions Single Cyclin T1 amino-acid mutations that impair Hexim1 binding are located on a groove between the two cyclin folds and define a surface overlapping the HIV-1 Tat protein binding surface. One residue, Y175, in the centre of this groove was identified as essential for both Hexim1 and Tat binding to P-TEFb as well as for HIV transcription. PMID:24985203

Cooperation enhanced by indirect reciprocity in spatial prisoner's dilemma games for social P2P systems

NASA Astrophysics Data System (ADS)

Tian, Lin-Lin; Li, Ming-Chu; Wang, Zhen

2016-11-01

With the growing interest in social Peer-to-Peer (P2P) applications, relationships of individuals are further exploited to improve the performances of reputation systems. It is an on-going challenge to investigate how spatial reciprocity aids indirect reciprocity in sustaining cooperation in practical P2P environments. This paper describes the construction of an extended prisoner's dilemma game on square lattice networks with three strategies, i.e., defection, unconditional cooperation, and reciprocal cooperation. Reciprocators discriminate partners according to their reputations based on image scoring, where mistakes in judgment of reputations may occur. The independent structures of interaction and learning neighborhood are discussed, with respect to the situation in which learning environments differ from interaction networks. The simulation results have indicated that the incentive mechanism enhances cooperation better in structured peers than among a well-mixed population. Given the realistic condition of inaccurate reputation scores, defection is still successfully held down when the players interact and learn within the unified neighborhoods. Extensive simulations have further confirmed the positive impact of spatial structure on cooperation with different sizes of lattice neighborhoods. And similar conclusions can also be drawn on regular random networks and scale-free networks. Moreover, for the separated structures of the neighborhoods, the interaction network has a critical effect on the evolution dynamics of cooperation and learning environments only have weaker impacts on the process. Our findings further provide some insights concerning the evolution of collective behaviors in social systems.

Parallel Processing of Adaptive Meshes with Load Balancing

NASA Technical Reports Server (NTRS)

Das, Sajal K.; Harvey, Daniel J.; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2001-01-01

Many scientific applications involve grids that lack a uniform underlying structure. These applications are often also dynamic in nature in that the grid structure significantly changes between successive phases of execution. In parallel computing environments, mesh adaptation of unstructured grids through selective refinement/coarsening has proven to be an effective approach. However, achieving load balance while minimizing interprocessor communication and redistribution costs is a difficult problem. Traditional dynamic load balancers are mostly inadequate because they lack a global view of system loads across processors. In this paper, we propose a novel and general-purpose load balancer that utilizes symmetric broadcast networks (SBN) as the underlying communication topology, and compare its performance with a successful global load balancing environment, called PLUM, specifically created to handle adaptive unstructured applications. Our experimental results on an IBM SP2 demonstrate that the SBN-based load balancer achieves lower redistribution costs than that under PLUM by overlapping processing and data migration.

Development of the functional social network index for adolescent and young adult cancer survivors.

PubMed

Huang, I-Chan; Jones, Conor M; Brinkman, Tara M; Hudson, Melissa M; Srivastava, D Kumar; Li, Yuelin; Robison, Leslie L; Krull, Kevin R

2018-05-15

To the authors' knowledge, social network status in adolescent and young adult (AYA) cancer survivors has not been adequately studied to date. The authors developed and validated a functional social network index (FSNI) for AYA survivors, and compared its performance with that of 2 traditional indices (density and betweenness centrality). A total of 102 AYA survivors and 102 noncancer controls who were matched for age, sex, and race were recruited from an Internet panel. Each participant reported relationships with up to 25 close friends and/or relatives. The authors developed a FSNI with reported marital status, contact frequency with friends/relatives, available resources for emotional and tangible support, and available resources for physical activity and weight management advice. Linear regression was used to analyze associations between the FSNI and cancer diagnoses, treatments, and coping skills. Based on the FSNI, survivors were found to have more available resources for emotional support (beta [b] = 3.02; P = .003), tangible support (b = 4.17; P<.001), physical activity advice (b = 3.94; P<.001), and weight management advice (b = 4.10; P<.001) compared with noncancer controls. Survivors of lymphoma had the largest FSNI, whereas survivors of central nervous system malignancies had the smallest (b = 2.77; P = .02). A higher FSNI was associated with better coping skills: less denial (b = 0.10; P = .01), using emotional support (b = 0.08; P = .04), using instrumental support (b = 0.12; P<.001), less behavioral disengagement (b = 0.08; P = .04), venting of emotions (b = 0.10; P = .004), positive reframing (b = 0.12; P = .003), planning for the future (b = 0.08; P = .03), and religious engagement (b = 0.16; P<.001). Density and betweenness centrality indices demonstrated neither significant differences in social networks between cancer survivors and controls (all P values >.05) nor significant associations with coping skills (all P values >.05). The FSNI appears to provide a better social network assessment for AYA cancer survivors than traditional indices. Cancer 2018;124:2220-7. © 2018 American Cancer Society. © 2018 American Cancer Society.

An unstructured mathematical model for growth of Pleurotus ostreatus on lignocellulosic material in solid-state fermentation systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarikaya, A.; Ladisch, M.R.

1997-01-01

Inedible plant material, generated in a Controlled Ecological Life Support System (CELSS), should be recycled preferably by bioregenerative methods that utilize enzymes or micro-organisms. This material consists of hemicellulose, cellulose, and lignin with the lignin fraction representing a recalcitrant component that is not readily treated by enzymatic methods. Consequently, the white-rot fungus, Pleurotus ostreatus, is attractive since it effectively degrades lignin and produces edible mushrooms. This work describes an unstructured model for the growth of P. ostreatus in a solid-state fermentation system using lignocellulosic plant materials from Brassica napus (rapeseed) as a substrate at three different particle sizes. A logisticmore » function model based on area was found to fit the surface growth of the mycelium on the solid substrate with respect to time, whereas a model based on diameter, alone, did not fit the data as well. The difference between the two measures of growth was also evident for mycelial growth in a bioreactor designed to facilitate a slow flowrate of air through the 1.5 cm thick mat of lignocellulosic biomass particles. The result is consistent with the concept of competition of the mycelium for the substrate that surrounds it, rather than just substrate that is immediately available to single cells. This approach provides a quantitative measure of P. ostreatus growth on lignocellulosic biomass in a solid-state fermentation system. The experimental data show that the best growth is obtained for the largest particles (1 cm) of the lignocellulosic substrate. 13 refs., 6 figs., 2 tabs.« less

Comparison of Sonar Discrimination by an Echolocating Dolphin and a Counterpropagation Neural Network

DTIC Science & Technology

1992-09-01

having a Roitblat et al. (1989) used a counterpropaga- half-power width of 264 ps. A width of 264 ps was tion network to emulate a d6lphin performing a...46- iis sfo M ) t ( ,, -oore. P.U S., Roitblat , HL., Penner, RN., and 0 44 0+ 0; 0 00 -06 -04 4)2 Nachtl lli, P,, (11191). Neural Networks 4, 11t1 J...wAtt tHIC5NtG:5tttlt~tN WmmI Roitblat , H L , Monte, P.W.I-, Nachtlgall. P It.i ~ Penner, •,H_, and Au. V.W.L (1949), Intern D i~tiby +---- Wig 1

Mapping Local Protein Electrostatics by EPR of pH-Sensitive Thiol-Specific Nitroxide† ¶

PubMed Central

Voinov, Maxim A.; Ruuge, Andres; Reznikov, Vladimir A.; Grigor’ev, Igor A.; Smirnov, Alex I.

2013-01-01

A first thiol-specific pH-sensitive nitroxide spin label of the imidazolidine series -methanethiosulfonic acid S-(1-oxyl-2,2,3,5,5-pentamethylimidazolidin-4-ylmethyl) ester (IMTSL) - has been synthesized and characterized. X- (9 GHz) and W-band (94 GHz) EPR spectral parameters of the new spin label in its free form and covalently attached to an amino acid cysteine and a tripeptide glutathione were studied as a function of pH and solvent polarity. pKa value of protonatable tertiary amino group of the spin label was found to be unaffected by other ionizable groups present in side chains of unstructured small peptides. The W-band EPR spectra were shown to allow for pKa determination from precise g-factor measurements. Is has been demonstrated that high accuracy of pKa determination for pH-sensitive nitroxides could be achieved regardless the frequency of measurements or the regime of spin exchange: fast at X-band and slow at W-band. IMTSL was found to react specifically with a model protein - iso-1-cytochrome c from yeast Saccharomyces cerevisiae - giving EPR spectra very similar to those of the most commonly employed cysteine-specific label MTSL. CD data indicated no perturbations to the overall protein structure upon IMTSL labeling. It was found that for IMTSL, giso correlates linearly with Aiso but the slopes are different for the neutral and charged forms of the nitroxide. This finding was attributed to the solvent effects on the spin density at the oxygen atom of the N–O group and on the excitation energy of the oxygen lone-pair orbital. PMID:18426227

Estimating temporal and spatial variation of ocean surface pCO2 in the North Pacific using a Self Organizing Map neural network technique

NASA Astrophysics Data System (ADS)

Nakaoka, S.; Telszewski, M.; Nojiri, Y.; Yasunaka, S.; Miyazaki, C.; Mukai, H.; Usui, N.

2013-03-01

This study produced maps of the partial pressure of oceanic carbon dioxide (pCO2sea) in the North Pacific on a 0.25° latitude × 0.25° longitude grid from 2002 to 2008. The pCO2sea values were estimated by using a self-organizing map neural network technique to explain the non-linear relationships between observed pCO2sea data and four oceanic parameters: sea surface temperature (SST), mixed layer depth, chlorophyll a concentration, and sea surface salinity (SSS). The observed pCO2sea data was obtained from an extensive dataset generated by the volunteer observation ship program operated by the National Institute for Environmental Studies. The reconstructed pCO2sea values agreed rather well with the pCO2sea measurements, the root mean square error being 17.6 μatm. The pCO2sea estimates were improved by including SSS as one of the training parameters and by taking into account secular increases of pCO2sea that have tracked increases in atmospheric CO2. Estimated pCO2sea values accurately reproduced pCO2sea data at several stations in the North Pacific. The distributions of pCO2sea revealed by seven-year averaged monthly pCO2sea maps were similar to Lamont-Doherty Earth Observatory pCO2sea climatology and more precisely reflected oceanic conditions. The distributions of pCO2sea anomalies over the North Pacific during the winter clearly showed regional contrasts between El Niño and La Niña years related to changes of SST and vertical mixing.

Secure Peer-to-Peer Networks for Scientific Information Sharing

NASA Technical Reports Server (NTRS)

Karimabadi, Homa

2012-01-01

The most common means of remote scientific collaboration today includes the trio of e-mail for electronic communication, FTP for file sharing, and personalized Web sites for dissemination of papers and research results. With the growth of broadband Internet, there has been a desire to share large files (movies, files, scientific data files) over the Internet. Email has limits on the size of files that can be attached and transmitted. FTP is often used to share large files, but this requires the user to set up an FTP site for which it is hard to set group privileges, it is not straightforward for everyone, and the content is not searchable. Peer-to-peer technology (P2P), which has been overwhelmingly successful in popular content distribution, is the basis for development of a scientific collaboratory called Scientific Peer Network (SciPerNet). This technology combines social networking with P2P file sharing. SciPerNet will be a standalone application, written in Java and Swing, thus insuring portability to a number of different platforms. Some of the features include user authentication, search capability, seamless integration with a data center, the ability to create groups and social networks, and on-line chat. In contrast to P2P networks such as Gnutella, Bit Torrent, and others, SciPerNet incorporates three design elements that are critical to application of P2P for scientific purposes: User authentication, Data integrity validation, Reliable searching SciPerNet also provides a complementary solution to virtual observatories by enabling distributed collaboration and sharing of downloaded and/or processed data among scientists. This will, in turn, increase scientific returns from NASA missions. As such, SciPerNet can serve a two-fold purpose for NASA: a cost-savings software as well as a productivity tool for scientists working with data from NASA missions.

Progression of Brain Network Alterations in Cerebral Amyloid Angiopathy.

PubMed

Reijmer, Yael D; Fotiadis, Panagiotis; Riley, Grace A; Xiong, Li; Charidimou, Andreas; Boulouis, Gregoire; Ayres, Alison M; Schwab, Kristin; Rosand, Jonathan; Gurol, M Edip; Viswanathan, Anand; Greenberg, Steven M

2016-10-01

We recently showed that cerebral amyloid angiopathy (CAA) is associated with functionally relevant brain network impairments, in particular affecting posterior white matter connections. Here we examined how these brain network impairments progress over time. Thirty-three patients with probable CAA underwent multimodal brain magnetic resonance imaging at 2 time points (mean follow-up time: 1.3±0.4 years). Brain networks of the hemisphere free of intracerebral hemorrhages were reconstructed using fiber tractography and graph theory. The global efficiency of the network and mean fractional anisotropies of posterior-posterior, frontal-frontal, and posterior-frontal network connections were calculated. Patients with moderate versus severe CAA were defined based on microbleed count, dichotomized at the median (median=35). Global efficiency of the intracerebral hemorrhage-free hemispheric network declined from baseline to follow-up (-0.008±0.003; P=0.029). The decline in global efficiency was most pronounced for patients with severe CAA (group×time interaction P=0.03). The decline in global network efficiency was associated with worse executive functioning (β=0.46; P=0.03). Examination of subgroups of network connections revealed a decline in fractional anisotropies of posterior-posterior connections at both levels of CAA severity (-0.006±0.002; P=0.017; group×time interaction P=0.16). The fractional anisotropies of posterior-frontal and frontal-frontal connections declined in patients with severe but not moderate CAA (group×time interaction P=0.007 and P=0.005). Associations were independent of change in white matter hyperintensity volume. Brain network impairment in patients with CAA worsens measurably over just 1.3-year follow-up and seem to progress from posterior to frontal connections with increasing disease severity. © 2016 American Heart Association, Inc.

Functional Topology of Evolving Urban Drainage Networks

NASA Astrophysics Data System (ADS)

Yang, Soohyun; Paik, Kyungrock; McGrath, Gavan S.; Urich, Christian; Krueger, Elisabeth; Kumar, Praveen; Rao, P. Suresh C.

2017-11-01

We investigated the scaling and topology of engineered urban drainage networks (UDNs) in two cities, and further examined UDN evolution over decades. UDN scaling was analyzed using two power law scaling characteristics widely employed for river networks: (1) Hack's law of length (L)-area (A) [L∝Ah] and (2) exceedance probability distribution of upstream contributing area (δ) [P>(A≥δ>)˜aδ-ɛ]. For the smallest UDNs (<2 km2), length-area scales linearly (h ˜ 1), but power law scaling (h ˜ 0.6) emerges as the UDNs grow. While P>(A≥δ>) plots for river networks are abruptly truncated, those for UDNs display exponential tempering [P>(A≥δ>)=aδ-ɛexp⁡>(-cδ>)]. The tempering parameter c decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power law exponent ɛ for large UDNs tends to be greater than the range reported for river networks. Differences in generative processes and engineering design constraints contribute to observed differences in the evolution of UDNs and river networks, including subnet heterogeneity and nonrandom branching.

A Web 2.0 and Epidemiology Mash-Up: Using respondent-driven sampling in combination with social network site recruitment to reach young transwomen

PubMed Central

Arayasirikul, Sean; Chen, Yea-Hung; Jin, Harry; Wilson, Erin

2015-01-01

Respondent-driven sampling (RDS) peer referral has been proven to be an effective recruitment method for hard-to-reach populations; however, its application in diverse populations is limited. Recruitment occurred in two phases: RDS-only followed by development and implementation of an online social network strategy in combination with RDS peer referral (RDS+SNS). Compared to RDS-only, RDS+SNS reached a sample that was younger (χ2=9.19, P = .03), more likely to identify with a non-binary gender identity (χ2=10.4247, P = .03), with less housing instability (50.5% vs. 68.6%, χ2=9.0038, P = .002) and less sex work (19.7% vs. 31.4%, χ2=5.0798, P = .02). Additionally, we describe lessons learned as a result of implementing our online social network strategy. Our findings underscore the importance of integrating Internet-driven strategies to meet challenges in sample diversity and recruitment of young transwomen. PMID:26499337

Dynamic Rupture Modeling in Three Dimensions on Unstructured Meshes Using a Discontinuous Galerkin Method

NASA Astrophysics Data System (ADS)

Pelties, C.; Käser, M.

2010-12-01

We will present recent developments concerning the extensions of the ADER-DG method to solve three dimensional dynamic rupture problems on unstructured tetrahedral meshes. The simulation of earthquake rupture dynamics and seismic wave propagation using a discontinuous Galerkin (DG) method in 2D was recently presented by J. de la Puente et al. (2009). A considerable feature of this study regarding spontaneous rupture problems was the combination of the DG scheme and a time integration method using Arbitrarily high-order DERivatives (ADER) to provide high accuracy in space and time with the discretization on unstructured meshes. In the resulting discrete velocity-stress formulation of the elastic wave equations variables are naturally discontinuous at the interfaces between elements. The so-called Riemann problem can then be solved to obtain well defined values of the variables at the discontinuity itself. This is in particular valid for the fault at which a certain friction law has to be evaluated. Hence, the fault’s geometry is honored by the computational mesh. This way, complex fault planes can be modeled adequately with small elements while fast mesh coarsening is possible with increasing distance from the fault. Due to the strict locality of the scheme using only direct neighbor communication, excellent parallel behavior can be observed. A further advantage of the scheme is that it avoids spurious high-frequency contributions in the slip rate spectra and therefore does not require artificial Kelvin-Voigt damping or filtering of synthetic seismograms. In order to test the accuracy of the ADER-DG method the Southern California Earthquake Center (SCEC) benchmark for spontaneous rupture simulations was employed. Reference: J. de la Puente, J.-P. Ampuero, and M. Käser (2009), Dynamic rupture modeling on unstructured meshes using a discontinuous Galerkin method, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, B10302, doi:10.1029/2008JB006271

The human phosphotyrosine signaling network: Evolution and hotspots of hijacking in cancer

PubMed Central

Li, Lei; Tibiche, Chabane; Fu, Cong; Kaneko, Tomonori; Moran, Michael F.; Schiller, Martin R.; Li, Shawn Shun-Cheng; Wang, Edwin

2012-01-01

Phosphotyrosine (pTyr) signaling, which plays a central role in cell–cell and cell–environment interactions, has been considered to be an evolutionary innovation in multicellular metazoans. However, neither the emergence nor the evolution of the human pTyr signaling system is currently understood. Tyrosine kinase (TK) circuits, each of which consists of a TK writer, a kinase substrate, and a related reader, such as Src homology (SH) 2 domains and pTyr-binding (PTB) domains, comprise the core machinery of the pTyr signaling network. In this study, we analyzed the evolutionary trajectories of 583 literature-derived and 50,000 computationally predicted human TK circuits in 19 representative eukaryotic species and assigned their evolutionary origins. We found that human TK circuits for intracellular pTyr signaling originated largely from primitive organisms, whereas the inter- or extracellular signaling circuits experienced significant expansion in the bilaterian lineage through the “back-wiring” of newly evolved kinases to primitive substrates and SH2/PTB domains. Conversely, the TK circuits that are involved in tissue-specific signaling evolved mainly in vertebrates by the back-wiring of vertebrate substrates to primitive kinases and SH2/PTB domains. Importantly, we found that cancer signaling preferentially employs the pTyr sites, which are linked to more TK circuits. Our work provides insights into the evolutionary paths of the human pTyr signaling circuits and suggests the use of a network approach for cancer intervention through the targeting of key pTyr sites and their associated signaling hubs in the network. PMID:22194470

Effects of Hospital Workers' Friendship Networks on Job Stress.

PubMed

Shin, Sung Yae; Lee, Sang Gyu

2016-01-01

This study attempted to identify the sources of job stress according to job position and investigate how friendship networks affect job stress. Questionnaires based on The Health Professions Stress Inventory (HPSI) developed by Wolfgang experienced by healthcare providers were collected from 420 nurses, doctors and radiological technologists in two general hospitals in Korea by a multistage cluster sampling method. Multiple regression analysis was used to examine the effects of friendship networks on job stress after controlling for other factors. The severity of job stress differed according to level of job demands (p = .006); radiologic technologists experienced the least stress (45.4), nurses experienced moderate stress (52.4), and doctors experienced the most stress (53.6). Those with long-term friendships characterized by strong connections reported lower levels of stress than did those with weak ties to friends among nurses (1.3, p < .05) and radiological technologists (11.4, p < .01). The degree of cohesion among friends had a positive impact on the level of job stress experienced by nurses (8.2, p < .001) and radiological technologists (14.6, p < .1). Doctors who participated in workplace alumni meetings scored higher than those who did not. However, those who participated in alumni meetings outside the workplace showed the opposite tendency, scoring 9.4 (p < .05) lower than those who did not. The resources from their friendship network include both information and instrumental support. As most radiological technologists were male, their instrumental support positively affected their job stress (9.2, p < .05). Life information support was the primary positive contributor to control of nurses' (4.1, p < .05), radiological technologists' (8.0, p < .05) job stress. The strength and density of such friendship networks were related to job stress. Life information support from their friendship network was the primary positive contributor to control of job stress.

Effects of Hospital Workers’ Friendship Networks on Job Stress

PubMed Central

Shin, Sung Yae; Lee, Sang Gyu

2016-01-01

Background This study attempted to identify the sources of job stress according to job position and investigate how friendship networks affect job stress. Methods Questionnaires based on The Health Professions Stress Inventory (HPSI) developed by Wolfgang experienced by healthcare providers were collected from 420 nurses, doctors and radiological technologists in two general hospitals in Korea by a multistage cluster sampling method. Multiple regression analysis was used to examine the effects of friendship networks on job stress after controlling for other factors. Results The severity of job stress differed according to level of job demands (p = .006); radiologic technologists experienced the least stress (45.4), nurses experienced moderate stress (52.4), and doctors experienced the most stress (53.6). Those with long-term friendships characterized by strong connections reported lower levels of stress than did those with weak ties to friends among nurses (1.3, p < .05) and radiological technologists (11.4, p < .01). The degree of cohesion among friends had a positive impact on the level of job stress experienced by nurses (8.2, p < .001) and radiological technologists (14.6, p < .1). Doctors who participated in workplace alumni meetings scored higher than those who did not. However, those who participated in alumni meetings outside the workplace showed the opposite tendency, scoring 9.4 (p < .05) lower than those who did not. The resources from their friendship network include both information and instrumental support. As most radiological technologists were male, their instrumental support positively affected their job stress (9.2, p < .05). Life information support was the primary positive contributor to control of nurses’ (4.1, p < .05), radiological technologists’ (8.0, p < .05) job stress. Conclusion The strength and density of such friendship networks were related to job stress. Life information support from their friendship network was the primary positive contributor to control of job stress. PMID:26900945

Modulation of mutant Huntingtin aggregates and toxicity by human myeloid leukemia factors.

PubMed

Banerjee, Manisha; Datta, Moumita; Bhattacharyya, Nitai P

2017-01-01

Increased poly glutamine (polyQ) stretch at N-terminal of Huntingtin (HTT) causes Huntington's disease. HTT interacts with large number of proteins, although the preference for such interactions with wild type or mutated HTT protein remains largely unknown. HYPK, an intrinsically unstructured protein chaperone and interactor of mutant HTT was found to interact with myeloid leukemia factor 1 (MLF1) and 2 (MLF2). To identify the role of these two proteins in mutant HTT mediated aggregate formation and toxicity in a cell model, both the proteins were found to preferentially interact with the mutated N-terminal HTT. They significantly reduced the number of cells containing mutant HTT aggregates and subsequent apoptosis in Neuro2A cells. Additionally, in FRAP assay, mobile fraction of mutant HTT aggregates was increased in the presence of MLF1 or MLF2. Further, MLF1 could release transcription factors like p53, CBP and CREB from mutant HTT aggregates. Moreover, in HeLa cell co-expressing mutant HTT exon1 and full length MLF1, p53 was released from the aggregates, leading to the recovery of the expression of the GADD45A transcript, a p53 regulated gene. Taking together, these results showed that MLF1 and MLF2 modulated the formation of aggregates and induction of apoptosis as well as the expressions of genes indirectly. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Bibliography of Software Engineering Terms.

DTIC Science & Technology

1979-10-01

WHAT HAPPENS TO DATA, HOW DATA IS TRANSFORMED, AND HOW ONE CAN PARTITION THE PROCESS INTO SUBPROCESSES WITH A MINIMAL NEED OF DATA TRANSFERS. (DAN 323...ANSI-X3HI) 75 p 1 PARANORMAL TERMINATION UNSTRUCTURED ESCAPES (IN CONTROL) FROM A MODULE IN RESPONSE TO NORMAL EVENTS OR CONDITIONS. MODULES HAVING... PARANORMAL TERMINATIONS MAY YET EXHIBIT A FORM OF STRUCTURED CONTROL FLOW, IF PROPERLY CONFIGURED INTO " PARANORMAL EXTENSIONS" OF STRUCTURED PROGRAMMING

Rubber elasticity for percolation network consisting of Gaussian chains.

PubMed

Nishi, Kengo; Noguchi, Hiroshi; Sakai, Takamasa; Shibayama, Mitsuhiro

2015-11-14

A theory describing the elastic modulus for percolation networks of Gaussian chains on general lattices such as square and cubic lattices is proposed and its validity is examined with simulation and mechanical experiments on well-defined polymer networks. The theory was developed by generalizing the effective medium approximation (EMA) for Hookian spring network to Gaussian chain networks. From EMA theory, we found that the ratio of the elastic modulus at p, G to that at p = 1, G0, must be equal to G/G0 = (p - 2/f)/(1 - 2/f) if the position of sites can be determined so as to meet the force balance, where p is the degree of cross-linking reaction. However, the EMA prediction cannot be applicable near its percolation threshold because EMA is a mean field theory. Thus, we combine real-space renormalization and EMA and propose a theory called real-space renormalized EMA, i.e., REMA. The elastic modulus predicted by REMA is in excellent agreement with the results of simulations and experiments of near-ideal diamond lattice gels.

Rubber elasticity for percolation network consisting of Gaussian chains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishi, Kengo, E-mail: kengo.nishi@phys.uni-goettingen.de, E-mail: sakai@tetrapod.t.u-tokyo.ac.jp, E-mail: sibayama@issp.u-tokyo.ac.jp; Noguchi, Hiroshi; Shibayama, Mitsuhiro, E-mail: kengo.nishi@phys.uni-goettingen.de, E-mail: sakai@tetrapod.t.u-tokyo.ac.jp, E-mail: sibayama@issp.u-tokyo.ac.jp

2015-11-14

A theory describing the elastic modulus for percolation networks of Gaussian chains on general lattices such as square and cubic lattices is proposed and its validity is examined with simulation and mechanical experiments on well-defined polymer networks. The theory was developed by generalizing the effective medium approximation (EMA) for Hookian spring network to Gaussian chain networks. From EMA theory, we found that the ratio of the elastic modulus at p, G to that at p = 1, G{sub 0}, must be equal to G/G{sub 0} = (p − 2/f)/(1 − 2/f) if the position of sites can be determined somore » as to meet the force balance, where p is the degree of cross-linking reaction. However, the EMA prediction cannot be applicable near its percolation threshold because EMA is a mean field theory. Thus, we combine real-space renormalization and EMA and propose a theory called real-space renormalized EMA, i.e., REMA. The elastic modulus predicted by REMA is in excellent agreement with the results of simulations and experiments of near-ideal diamond lattice gels.« less

Use of Unstructured Event-Based Reports for Global Infectious Disease Surveillance

PubMed Central

Blench, Michael; Tolentino, Herman; Freifeld, Clark C.; Mandl, Kenneth D.; Mawudeku, Abla; Eysenbach, Gunther; Brownstein, John S.

2009-01-01

Free or low-cost sources of unstructured information, such as Internet news and online discussion sites, provide detailed local and near real-time data on disease outbreaks, even in countries that lack traditional public health surveillance. To improve public health surveillance and, ultimately, interventions, we examined 3 primary systems that process event-based outbreak information: Global Public Health Intelligence Network, HealthMap, and EpiSPIDER. Despite similarities among them, these systems are highly complementary because they monitor different data types, rely on varying levels of automation and human analysis, and distribute distinct information. Future development should focus on linking these systems more closely to public health practitioners in the field and establishing collaborative networks for alert verification and dissemination. Such development would further establish event-based monitoring as an invaluable public health resource that provides critical context and an alternative to traditional indicator-based outbreak reporting. PMID:19402953

Power, Status and Network Perceptions: The Effects of Network Bias on Organizational Outcomes

DTIC Science & Technology

2012-09-01

OF RESPONSIBLE PERSON Lisa Boyce a. REPORT UNCLAS b. ABSTRACT UNCLAS c. THIS PAGE UNCLAS 19b. TELEPHONE NUMBER (Include area code) +44 (0...with our prediction, we found that power was a significant predictor (B = .03, SE = .01, Wald χ² = 5.81, p < .01) while controlling for the actual...density of the advice network (B = 1.37, SE = .63, Wald χ² = 4.78, p < .05), likelihood ratio χ² (2, N = 124) = 206.13, p < .001. As before, we

Transport and percolation in complex networks

NASA Astrophysics Data System (ADS)

Li, Guanliang

To design complex networks with optimal transport properties such as flow efficiency, we consider three approaches to understanding transport and percolation in complex networks. We analyze the effects of randomizing the strengths of connections, randomly adding long-range connections to regular lattices, and percolation of spatially constrained networks. Various real-world networks often have links that are differentiated in terms of their strength, intensity, or capacity. We study the distribution P(σ) of the equivalent conductance for Erdoḧs-Rényi (ER) and scale-free (SF) weighted resistor networks with N nodes, for which links are assigned with conductance σ i ≡ e-axi, where xi is a random variable with 0 < xi < 1. We find, both analytically and numerically, that P(σ) for ER networks exhibits two regimes: (i) For σ < e-apc, P(σ) is independent of N and scales as a power law P(σ) ˜ sk/a-1 . Here pc = 1/ is the critical percolation threshold of the network and is the average degree of the network. (ii) For σ > e -apc, P(σ) has strong N dependence and scales as P(σ) ˜ f(σ, apc/N1/3). Transport properties are greatly affected by the topology of networks. We investigate the transport problem in lattices with long-range connections and subject to a cost constraint, seeking design principles for optimal transport networks. Our network is built from a regular d-dimensional lattice to be improved by adding long-range connections with probability Pij ˜ r-aij , where rij is the lattice distance between site i and j. We introduce a cost constraint on the total length of the additional links and find optimal transport in the system for α = d + 1, established here for d = 1, 2 and 3 for regular lattices and df for fractals. Remarkably, this cost constraint approach remains optimal, regardless of the strategy used for transport, whether based on local or global knowledge of the network structure. To further understand the role that long-range connections play in optimizing the transport of complex systems, we study the percolation of spatially constrained networks. We now consider originally empty lattices embedded in d dimensions by adding long-range connections with the same power law probability p(r) ˜ r -α. We find that, for α ≤ d, the percolation transition belongs to the universality class of percolation in ER networks, while for α > 2d it belongs to the universality class of percolation in regular lattices (for one-dimensional linear chain, there is no percolation transition). However for d < α < 2d, the percolation properties show new intermediate behavior different from ER networks, with critical exponents that depend on α.

Karhunen Loève approximation of random fields by generalized fast multipole methods

NASA Astrophysics Data System (ADS)

Schwab, Christoph; Todor, Radu Alexandru

2006-09-01

KL approximation of a possibly instationary random field a( ω, x) ∈ L2( Ω, d P; L∞( D)) subject to prescribed meanfield Ea(x)=∫a(ω,x) dP(ω) and covariance Va(x,x')=∫(a(ω,x)-Ea(x))(a(ω,x')-Ea(x')) dP(ω) in a polyhedral domain D⊂Rd is analyzed. We show how for stationary covariances Va( x, x') = ga(| x - x'|) with ga( z) analytic outside of z = 0, an M-term approximate KL-expansion aM( ω, x) of a( ω, x) can be computed in log-linear complexity. The approach applies in arbitrary domains D and for nonseparable covariances Ca. It involves Galerkin approximation of the KL eigenvalue problem by discontinuous finite elements of degree p ⩾ 0 on a quasiuniform, possibly unstructured mesh of width h in D, plus a generalized fast multipole accelerated Krylov-Eigensolver. The approximate KL-expansion aM( x, ω) of a( x, ω) has accuracy O(exp(- bM1/ d)) if ga is analytic at z = 0 and accuracy O( M- k/ d) if ga is Ck at zero. It is obtained in O( MN(log N) b) operations where N = O( h- d).

Carbon dioxide and methane dynamics in a human-dominated lowland coastal river network (Shanghai, China)

NASA Astrophysics Data System (ADS)

Yu, Zhongjie; Wang, Dongqi; Li, Yangjie; Deng, Huanguang; Hu, Beibei; Ye, Mingwu; Zhou, Xuhui; Da, Liangjun; Chen, Zhenlou; Xu, Shiyuan

2017-07-01

Evasion of carbon dioxide (CO2) and methane (CH4) in streams and rivers play a critical role in global carbon (C) cycle, offsetting the C uptake by terrestrial ecosystems. However, little is known about CO2 and CH4 dynamics in lowland coastal rivers profoundly modified by anthropogenic perturbations. Here we report results from a long-term, large-scale study of CO2 and CH4 partial pressures (pCO2 and pCH4) and evasion rates in the Shanghai river network. The spatiotemporal variabilities of pCO2 and pCH4 were examined along a land use gradient, and the annual CO2 and CH4 evasion were estimated to assess its role in regional C budget. During the study period (August 2009 to October 2011), the overall mean pCO2 and median pCH4 from 87 surveyed rivers were 5846 ± 2773 μatm and 241 μatm, respectively. Internal metabolic CO2 production and dissolved inorganic carbon input via upstream runoff were the major sources sustaining the widespread CO2 supersaturation, coupling pCO2 to biogeochemical and hydrological controls, respectively. While CH4 was oversaturated throughout the river network, CH4 hot spots were concentrated in the small urban rivers and highly discharge-dependent. The Shanghai river network played a disproportionately important role in regional C budget, offsetting up to 40% of the regional terrestrial net ecosystem production and 10% of net C uptake in the river-dominated East China Sea fueled by anthropogenic nutrient input. Given the rapid urbanization in global coastal areas, more research is needed to quantify the role of lowland coastal rivers as a major landscape C source in global C budget.

Modeling of the pyruvate production with Escherichia coli: comparison of mechanistic and neural networks-based models.

PubMed

Zelić, B; Bolf, N; Vasić-Racki, D

2006-06-01

Three different models: the unstructured mechanistic black-box model, the input-output neural network-based model and the externally recurrent neural network model were used to describe the pyruvate production process from glucose and acetate using the genetically modified Escherichia coli YYC202 ldhA::Kan strain. The experimental data were used from the recently described batch and fed-batch experiments [ Zelić B, Study of the process development for Escherichia coli-based pyruvate production. PhD Thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb, Croatia, July 2003. (In English); Zelić et al. Bioproc Biosyst Eng 26:249-258 (2004); Zelić et al. Eng Life Sci 3:299-305 (2003); Zelić et al Biotechnol Bioeng 85:638-646 (2004)]. The neural networks were built out of the experimental data obtained in the fed-batch pyruvate production experiments with the constant glucose feed rate. The model validation was performed using the experimental results obtained from the batch and fed-batch pyruvate production experiments with the constant acetate feed rate. Dynamics of the substrate and product concentration changes was estimated using two neural network-based models for biomass and pyruvate. It was shown that neural networks could be used for the modeling of complex microbial fermentation processes, even in conditions in which mechanistic unstructured models cannot be applied.

Constructing Social Networks from Unstructured Group Dialog in Virtual Worlds

NASA Astrophysics Data System (ADS)

Shah, Fahad; Sukthankar, Gita

Virtual worlds and massively multi-player online games are rich sources of information about large-scale teams and groups, offering the tantalizing possibility of harvesting data about group formation, social networks, and network evolution. However these environments lack many of the cues that facilitate natural language processing in other conversational settings and different types of social media. Public chat data often features players who speak simultaneously, use jargon and emoticons, and only erratically adhere to conversational norms. In this paper, we present techniques for inferring the existence of social links from unstructured conversational data collected from groups of participants in the Second Life virtual world. We present an algorithm for addressing this problem, Shallow Semantic Temporal Overlap (SSTO), that combines temporal and language information to create directional links between participants, and a second approach that relies on temporal overlap alone to create undirected links between participants. Relying on temporal overlap is noisy, resulting in a low precision and networks with many extraneous links. In this paper, we demonstrate that we can ameliorate this problem by using network modularity optimization to perform community detection in the noisy networks and severing cross-community links. Although using the content of the communications still results in the best performance, community detection is effective as a noise reduction technique for eliminating the extra links created by temporal overlap alone.

Integration of a splicing regulatory network within the meiotic gene expression program of Saccharomyces cerevisiae

PubMed Central

Munding, Elizabeth M.; Igel, A. Haller; Shiue, Lily; Dorighi, Kristel M.; Treviño, Lisa R.; Ares, Manuel

2010-01-01

Splicing regulatory networks are essential components of eukaryotic gene expression programs, yet little is known about how they are integrated with transcriptional regulatory networks into coherent gene expression programs. Here we define the MER1 splicing regulatory network and examine its role in the gene expression program during meiosis in budding yeast. Mer1p splicing factor promotes splicing of just four pre-mRNAs. All four Mer1p-responsive genes also require Nam8p for splicing activation by Mer1p; however, other genes require Nam8p but not Mer1p, exposing an overlapping meiotic splicing network controlled by Nam8p. MER1 mRNA and three of the four Mer1p substrate pre-mRNAs are induced by the transcriptional regulator Ume6p. This unusual arrangement delays expression of Mer1p-responsive genes relative to other genes under Ume6p control. Products of Mer1p-responsive genes are required for initiating and completing recombination and for activation of Ndt80p, the activator of the transcriptional network required for subsequent steps in the program. Thus, the MER1 splicing regulatory network mediates the dependent relationship between the UME6 and NDT80 transcriptional regulatory networks in the meiotic gene expression program. This study reveals how splicing regulatory networks can be interlaced with transcriptional regulatory networks in eukaryotic gene expression programs. PMID:21123654

MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

PubMed

Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Triviño

2013-01-01

In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

RENDEZVOUS: Self-Organizing Services in an Active Network

DTIC Science & Technology

2004-02-01

http://www.cs.washington.edu/research/networking/ants/, and http://www.cs.utah.edu/flux/janos/ants.html, 2001. [2] Krishna P. Gummadi, “King...Proceedings of the Tenth ACM SIGOPS European Workshop, September 2002. [9] Stefan Saroiu, P. Krishna Gummadi, Steven D. Gribble: A Measurement Study...Davis, Eric Lemar, and Brian Bershad. “Migration for Pervasive Applications.” Submitted to OSDI, June 2002. Gummadi, P. Krishna , Stefan Saroiu, and

Processable English: The Theory Behind the PENG System

DTIC Science & Technology

2009-06-01

implicit - is often buried amongst masses of irrelevant data. Heralding from unstructured sources such as natural language documents, email, audio ...estimation and prediction, data-mining, social network analysis, and semantic search and visualisation . This report describes the theoretical

Functional Tat transport of unstructured, small, hydrophilic proteins.

PubMed

Richter, Silke; Lindenstrauss, Ute; Lücke, Christian; Bayliss, Richard; Brüser, Thomas

2007-11-16

The twin-arginine translocation (Tat) system is a protein translocation system that is adapted to the translocation of folded proteins across biological membranes. An understanding of the folding requirements for Tat substrates is of fundamental importance for the elucidation of the transport mechanism. We now demonstrate for the first time Tat transport for fully unstructured proteins, using signal sequence fusions to naturally unfolded FG repeats from the yeast Nsp1p nuclear pore protein. The transport of unfolded proteins becomes less efficient with increasing size, consistent with only a single interaction between the system and the substrate. Strikingly, the introduction of six residues from the hydrophobic core of a globular protein completely blocked translocation. Physiological data suggest that hydrophobic surface patches abort transport at a late stage, most likely by membrane interactions during transport. This study thus explains the observed restriction of the Tat system to folded globular proteins on a molecular level.

Mobile Support For Logistics

DTIC Science & Technology

2016-03-01

Infrastructure to Support Mobile Devices (Takai, 2012, p. 2). The objectives needed in order to meet this goal are to: evolve spectrum management, expand... infrastructure to support wireless capabilities, and establish a mobile device security architecture (Takai, 2012, p. 2). By expanding infrastructure to...often used on Mobile Ad-Hoc Networks (MANETs). MANETS are infrastructure -less networks that include, but are not limited to, mobile devices. These

Spatial and Time Domain Feature of ERP Speller System Extracted via Convolutional Neural Network.

PubMed

Yoon, Jaehong; Lee, Jungnyun; Whang, Mincheol

2018-01-01

Feature of event-related potential (ERP) has not been completely understood and illiteracy problem remains unsolved. To this end, P300 peak has been used as the feature of ERP in most brain-computer interface applications, but subjects who do not show such peak are common. Recent development of convolutional neural network provides a way to analyze spatial and temporal features of ERP. Here, we train the convolutional neural network with 2 convolutional layers whose feature maps represented spatial and temporal features of event-related potential. We have found that nonilliterate subjects' ERP show high correlation between occipital lobe and parietal lobe, whereas illiterate subjects only show correlation between neural activities from frontal lobe and central lobe. The nonilliterates showed peaks in P300, P500, and P700, whereas illiterates mostly showed peaks in around P700. P700 was strong in both subjects. We found that P700 peak may be the key feature of ERP as it appears in both illiterate and nonilliterate subjects.

Spatial and Time Domain Feature of ERP Speller System Extracted via Convolutional Neural Network

PubMed Central

2018-01-01

Feature of event-related potential (ERP) has not been completely understood and illiteracy problem remains unsolved. To this end, P300 peak has been used as the feature of ERP in most brain–computer interface applications, but subjects who do not show such peak are common. Recent development of convolutional neural network provides a way to analyze spatial and temporal features of ERP. Here, we train the convolutional neural network with 2 convolutional layers whose feature maps represented spatial and temporal features of event-related potential. We have found that nonilliterate subjects' ERP show high correlation between occipital lobe and parietal lobe, whereas illiterate subjects only show correlation between neural activities from frontal lobe and central lobe. The nonilliterates showed peaks in P300, P500, and P700, whereas illiterates mostly showed peaks in around P700. P700 was strong in both subjects. We found that P700 peak may be the key feature of ERP as it appears in both illiterate and nonilliterate subjects.

Video-based peer feedback through social networking for robotic surgery simulation: a multicenter randomized controlled trial.

PubMed

Carter, Stacey C; Chiang, Alexander; Shah, Galaxy; Kwan, Lorna; Montgomery, Jeffrey S; Karam, Amer; Tarnay, Christopher; Guru, Khurshid A; Hu, Jim C

2015-05-01

To examine the feasibility and outcomes of video-based peer feedback through social networking to facilitate robotic surgical skill acquisition. The acquisition of surgical skills may be challenging for novel techniques and/or those with prolonged learning curves. Randomized controlled trial involving 41 resident physicians performing the Tubes (Da Vinci Intuitive Surgical, Sunnyvale, CA) simulator exercise with versus without peer feedback of video-recorded performance through a social networking Web page. Data collected included simulator exercise score, time to completion, and comfort and satisfaction with robotic surgery simulation. There were no baseline differences between the intervention group (n = 20) and controls (n = 21). The intervention group showed improvement in mean scores from session 1 to sessions 2 and 3 (60.7 vs 75.5, P < 0.001, and 60.7 vs 80.1, P < 0.001, respectively). The intervention group scored significantly higher than controls at sessions 2 and 3 (75.5 vs 59.6, P = 0.009, and 80.1 vs 65.9, P = 0.019, respectively). The mean time (seconds) to complete the task was shorter for the intervention group than for controls during sessions 2 and 3 (217.4 vs 279.0, P = 0.004, and 201.4 vs 261.9, P = 0.006, respectively). At the study conclusion, feedback subjects were more comfortable with robotic surgery than controls (90% vs 62%, P = 0.021) and expressed greater satisfaction with the learning experience (100% vs 67%, P = 0.014). Of the intervention subjects, 85% found that peer feedback was useful and 100% found it effective. Video-based peer feedback through social networking appears to be an effective paradigm for surgical education and accelerates the robotic surgery learning curve during simulation.

A new scripting library for modeling flow and transport in fractured rock with channel networks

NASA Astrophysics Data System (ADS)

Dessirier, Benoît; Tsang, Chin-Fu; Niemi, Auli

2018-02-01

Deep crystalline bedrock formations are targeted to host spent nuclear fuel owing to their overall low permeability. They are however highly heterogeneous and only a few preferential paths pertaining to a small set of dominant rock fractures usually carry most of the flow or mass fluxes, a behavior known as channeling that needs to be accounted for in the performance assessment of repositories. Channel network models have been developed and used to investigate the effect of channeling. They are usually simpler than discrete fracture networks based on rock fracture mappings and rely on idealized full or sparsely populated lattices of channels. This study reexamines the fundamental parameter structure required to describe a channel network in terms of groundwater flow and solute transport, leading to an extended description suitable for unstructured arbitrary networks of channels. An implementation of this formalism in a Python scripting library is presented and released along with this article. A new algebraic multigrid preconditioner delivers a significant speedup in the flow solution step compared to previous channel network codes. 3D visualization is readily available for verification and interpretation of the results by exporting the results to an open and free dedicated software. The new code is applied to three example cases to verify its results on full uncorrelated lattices of channels, sparsely populated percolation lattices and to exemplify the use of unstructured networks to accommodate knowledge on local rock fractures.

Multiple-Optimizing Dynamic Sensor Networks with MIMO Technology (PREPRINT)

DTIC Science & Technology

2010-06-01

a) where PAP is the power consumption dependent on the transmit power , cP is the power consumption dependent on the transceiver circuit...w’s parent p received new’s request, p adds new into its backbone list and sets d(p, new) = 2d; p sends the kowledge it holds to new

A multi-tiered architecture for content retrieval in mobile peer-to-peer networks.

DOT National Transportation Integrated Search

2012-01-01

In this paper, we address content retrieval in Mobile Peer-to-Peer (P2P) Networks. We design a multi-tiered architecture for content : retrieval, where at Tier 1, we design a protocol for content similarity governed by a parameter that trades accu...

Conserved Regulation of p53 Network Dosage by MicroRNA–125b Occurs through Evolving miRNA–Target Gene Pairs

PubMed Central

Khaw, Swea Ling; Chin, Lingzi; Teh, Cathleen; Tay, Junliang; O'Day, Elizabeth; Korzh, Vladimir; Yang, Henry; Lal, Ashish; Lieberman, Judy; Lodish, Harvey F.; Lim, Bing

2011-01-01

MicroRNAs regulate networks of genes to orchestrate cellular functions. MiR-125b, the vertebrate homologue of the Caenorhabditis elegans microRNA lin-4, has been implicated in the regulation of neural and hematopoietic stem cell homeostasis, analogous to how lin-4 regulates stem cells in C. elegans. Depending on the cell context, miR-125b has been proposed to regulate both apoptosis and proliferation. Because the p53 network is a central regulator of both apoptosis and proliferation, the dual roles of miR-125b raise the question of what genes in the p53 network might be regulated by miR-125b. By using a gain- and loss-of-function screen for miR-125b targets in humans, mice, and zebrafish and by validating these targets with the luciferase assay and a novel miRNA pull-down assay, we demonstrate that miR-125b directly represses 20 novel targets in the p53 network. These targets include both apoptosis regulators like Bak1, Igfbp3, Itch, Puma, Prkra, Tp53inp1, Tp53, Zac1, and also cell-cycle regulators like cyclin C, Cdc25c, Cdkn2c, Edn1, Ppp1ca, Sel1l, in the p53 network. We found that, although each miRNA–target pair was seldom conserved, miR-125b regulation of the p53 pathway is conserved at the network level. Our results lead us to propose that miR-125b buffers and fine-tunes p53 network activity by regulating the dose of both proliferative and apoptotic regulators, with implications for tissue stem cell homeostasis and oncogenesis. PMID:21935352

Neutron structure of human carbonic anhydrase II: a hydrogen-bonded water network "switch" is observed between pH 7.8 and 10.0.

PubMed

Fisher, Zoë; Kovalevsky, Andrey Y; Mustyakimov, Marat; Silverman, David N; McKenna, Robert; Langan, Paul

2011-11-08

The neutron structure of wild-type human carbonic anhydrase II at pH 7.8 has been determined to 2.0 Å resolution. Detailed analysis and comparison to the previously determined structure at pH 10.0 show important differences in the protonation of key catalytic residues in the active site as well as a rearrangement of the H-bonded water network. For the first time, a completed H-bonded network stretching from the Zn-bound solvent to the proton shuttling residue, His64, has been directly observed.

Changes in Brain Structural Networks and Cognitive Functions in Testicular Cancer Patients Receiving Cisplatin-Based Chemotherapy.

PubMed

Amidi, Ali; Hosseini, S M Hadi; Leemans, Alexander; Kesler, Shelli R; Agerbæk, Mads; Wu, Lisa M; Zachariae, Robert

2017-12-01

Cisplatin-based chemotherapy may have neurotoxic effects within the central nervous system. The aims of this study were 1) to longitudinally investigate the impact of cisplatin-based chemotherapy on whole-brain networks in testicular cancer patients undergoing treatment and 2) to explore whether possible changes are related to decline in cognitive functioning. Sixty-four newly orchiectomized TC patients underwent structural magnetic resonance imaging (T1-weighted and diffusion-weighted imaging) and cognitive testing at baseline prior to further treatment and again at a six-month follow-up. At follow-up, 22 participants had received cisplatin-based chemotherapy (CT) while 42 were in active surveillance (S). Brain structural networks were constructed for each participant, and network properties were investigated using graph theory and longitudinally compared across groups. Cognitive functioning was evaluated using standardized neuropsychological tests. All statistical tests were two-sided. Compared with the S group, the CT group demonstrated altered global and local brain network properties from baseline to follow-up as evidenced by decreases in important brain network properties such as small-worldness (P = .04), network clustering (P = .04), and local efficiency (P = .02). In the CT group, poorer overall cognitive performance was associated with decreased small-worldness (r = -0.46, P = .04) and local efficiency (r = -0.51, P = .02), and verbal fluency was associated with decreased local efficiency (r = -0.55, P = .008). Brain structural networks may be disrupted following treatment with cisplatin-based chemotherapy. Impaired brain networks may underlie poorer performance over time on both specific and nonspecific cognitive functions in patients undergoing chemotherapy. To the best of our knowledge, this is the first study to longitudinally investigate changes in structural brain networks in a cancer population, providing novel insights regarding the neurobiological mechanisms of cancer-related cognitive impairment.

Convergence of Internet and TV: The Commercial Viability of P2P Content Delivery

NASA Astrophysics Data System (ADS)

de Boever, Jorn

The popularity of (illegal) P2P (peer-to-peer) file sharing has a disruptive impact on Internet traffic and business models of content providers. In addition, several studies have found an increasing demand for bandwidth consuming content, such as video, on the Internet. Although P2P systems have been put forward as a scalable and inexpensive model to deliver such content, there has been relatively little economic analysis of the potentials and obstacles of P2P systems as a legal and commercial content distribution model. Many content providers encounter uncertainties regarding the adoption or rejection of P2P networks to spread content over the Internet. The recent launch of several commercial, legal P2P content distribution platforms increases the importance of an integrated analysis of the Strengths, Weaknesses, Opportunities and Threats (SWOT).

Characteristics of Resting-State Functional Connectivity in Intractable Unilateral Temporal Lobe Epilepsy Patients with Impaired Executive Control Function

PubMed Central

Zhang, Chao; Yang, Hongyu; Qin, Wen; Liu, Chang; Qi, Zhigang; Chen, Nan; Li, Kuncheng

2017-01-01

Executive control function (ECF) deficit is a common complication of temporal lobe epilepsy (TLE). Characteristics of brain network connectivity in TLE with ECF dysfunction are still unknown. The aim of this study was to investigate resting-state functional connectivity (FC) changes in patients with unilateral intractable TLE with impaired ECF. Forty right-handed patients with left TLE confirmed by comprehensive preoperative evaluation and postoperative pathological findings were enrolled. The patients were divided into normal ECF (G1) and decreased ECF (G2) groups according to whether they showed ECF impairment on the Wisconsin Card Sorting Test (WCST). Twenty-three healthy volunteers were recruited as the healthy control (HC) group. All subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI). Group-information-guided independent component analysis (GIG-ICA) was performed to estimate resting-state networks (RSNs) for all subjects. General linear model (GLM) was employed to analyze intra-network FC (p < 0.05, false discovery rate, FDR correction) and inter-network FC (p < 0.05, Bonferroni correction) of RSN among three groups. Pearson correlations between FC and neuropsychological tests were also determined through partial correlation analysis (p < 0.05). Eleven meaningful RSNs were identified from 40 left TLE and 23 HC subjects. Comparison of intra-network FC of all 11 meaningful RSNs did not reveal significant difference among the three groups (p > 0.05, FDR correction). For inter-network analysis, G2 exhibited decreased FC between the executive control network (ECN) and default-mode network (DMN) when compared with G1 (p = 0.000, Bonferroni correction) and HC (p = 0.000, Bonferroni correction). G1 showed no significant difference of FC between ECN and DMN when compared with HC. Furthermore, FC between ECN and DMN had significant negative correlation with perseverative responses (RP), response errors (RE) and perseverative errors (RPE) and had significant positive correlation categories completed (CC) in both G1 and G2 (p < 0.05). No significant difference of Montreal Cognitive Assessment (MoCA) was found between G1 and G2, while intelligence quotient (IQ) testing showed significant difference between G1and G2.There was no correlation between FC and either MoCA or IQ performance. Our findings suggest that ECF impairment in unilateral TLE is not confined to the diseased temporal lobe. Decreased FC between DMN and ECN may be an important characteristic of RSN in intractable unilateral TLE. PMID:29375338

Quantum Cosmology

NASA Astrophysics Data System (ADS)

Bojowald, Martin

The universe, ultimately, is to be described by quantum theory. Quantum aspects of all there is, including space and time, may not be significant for many purposes, but are crucial for some. And so a quantum description of cosmology is required for a complete and consistent worldview. At any rate, even if we were not directly interested in regimes where quantum cosmology plays a role, a complete physical description could not stop at a stage before the whole universe is reached. Quantum theory is essential in the microphysics of particles, atoms, molecules, solids, white dwarfs and neutron stars. Why should one expect this ladder of scales to end at a certain size? If regimes are sufficiently violent and energetic, quantum effects are non-negligible even on scales of the whole cosmos; this is realized at least once in the history of the universe: at the big bang where the classical theory of general relativity would make energy densities diverge. 1.Lachieze-Rey, M., Luminet, J.P.: Phys. Rept. 254,135 (1995), gr-qc/9605010 2.BSDeWitt1967Phys. Rev.160511131967PhRv..160.1113D0158.4650410.1103/PhysRev.160.1113DeWitt, B.S.: Phys. Rev. 160(5), 1113 (1967) 3.Wiltshire, D.L.: In: Robson B., Visvanathan N., Woolcock W.S. (eds.) Cosmology: The Physics of the Universe, pp. 473-531. World Scientific, Singapore (1996). gr-qc/0101003 4.Isham C.J.: In: DeWitt, B.S., Stora, R. (eds.) Relativity, Groups and Topology II. Lectures Given at the 1983 Les Houches Summer School on Relativity, Groups and Topology, Elsevier Science Publishing Company (1986) 5.Klauder, J.: Int. J. Mod. Phys. D 12, 1769 (2003), gr-qc/0305067 6.Klauder, J.: Int. J. Geom. Meth. Mod. Phys. 3, 81 (2006), gr-qc/0507113 7.DGiulini1995Phys. Rev. D5110563013381161995PhRvD..51.5630G10.1103/PhysRevD.51.5630Giulini, D.: Phys. Rev. D 51(10), 5630 (1995) 8.Kiefer, C., Zeh, H.D.: Phys. Rev. D 51, 4145 (1995), gr-qc/9402036 9.WFBlythCJIsham1975Phys. Rev. D117684086991975PhRvD..11..768B10.1103/PhysRevD.11.768Blyth, W.F., Isham, C.J.: Phys. Rev. D 11, 768 (1975) 10.JDBrownKVKuchař1995Phys. Rev. D51560013381151995PhRvD..51.5600B10.1103/PhysRevD.51.5600Brown, J.D., Kuchař, K.V.: Phys. Rev. D 51, 5600 (1995) 11.Alvarenga, F.G., Fabris, J.C., Lemos, N.A., Monerat, G.A.: Gen. Rel. Grav. 34, 651 (2002), gr-qc/0106051 12.JAcaciode BarrosNPinto-NetoMASagiaro-Leal1998Phys. Lett. A.2412291998PhLA..241..229D10.1016/S0375-9601(98)00169-8Acacio de Barros, J., Pinto-Neto, N., Sagiaro-Leal, M.A.: Phys. Lett. A. 241, 229 (1998), gr-qc/9710084 13.DBohm1952Phys. Rev.85166462871952PhRv...85..166B0046.2100410.1103/PhysRev.85.166Bohm, D.: Phys. Rev. 85, 166 (1952) 14.DBohm1952Phys. Rev.85180462881952PhRv...85..180B10.1103/PhysRev.85.180Bohm, D.: Phys. Rev. 85, 180 (1952) 15.DBohm1953Phys. Rev.89458669531953PhRv...89..458B0051.2050210.1103/PhysRev.89.458Bohm, D.: Phys. Rev. 89, 458 (1953) 16.Goldstein, S.: Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/qm-bohm/ 17.RColisteteJrJCFabrisNPinto-Neto2000Phys. Rev. D620835072000PhRvD..62h3507C10.1103/PhysRevD.62.083507Colistete, R. Jr, Fabris, J.C., Pinto-Neto, N.: Phys. Rev. D 62, 083507 (2000), gr-qc/0005013 18.FTFalcianoNPinto-NetoESSantini2007Phys. Rev. D760835212007PhRvD..76h3521F10.1103/PhysRevD.76.083521Falciano, F.T., Pinto-Neto, N., Santini, E.S.: Phys. Rev. D 76, 083521 (2007), arXiv:0707.1088 19.FTFalcianoNPinto-Neto2009Phys. Rev. D7902350724911632009PhRvD..79b3507F10.1103/PhysRevD.79.023507Falciano, F.T., Pinto-Neto, N.: Phys. Rev. D 79, 023507 (2009), arXiv:0810.3542 20.AShojaiFShojai2005Europhys. Lett.718862005EL.....71..886S10.1209/epl/i2005-10186-yShojai, A., Shojai, F.: Europhys. Lett. 71, 886 (2005), gr-qc/0409020 21.RBGriffiths1993Phys. Rev. Lett.70220112145601993PhRvL..70.2201G1051.8150610.1103/PhysRevLett.70.2201Griffiths, R.B.: Phys. Rev. Lett. 70, 2201 (1993) 22.ROmnés1992Rev. Mod. Phys.643391992RvMP...64..339O10.1103/RevModPhys.64.339Omnés, R.: Rev. Mod. Phys. 64, 339 (1992) 23.MGell-MannJBHartle1993Phys. Rev. D47334512188231993PhRvD..47.3345G10.1103/PhysRevD.47.3345Gell-Mann, M., Hartle, J.B.: Phys. Rev. D 47, 3345 (1993), gr-qc/9210010 24.FDowkerAKent1996J. Statist. Phys.82157513749291996JSP....82.1575D1042.8150710.1007/BF02183396Dowker, F., Kent, A.: J. Statist. Phys. 82, 1575 (1996), gr-qc/9412067 25.Dias, N.C., Mikovic, A, Prata, J.N.: J. Math. Phys. 47, 082101 (2006), hep-th/0507255 26.MBojowaldASkirzewski2006Rev. Math. Phys.1871322671131124.8201010.1142/S0129055X06002772Bojowald, M., Skirzewski, A.: Rev. Math. Phys. 18, 713 (2006), math-ph/0511043 27.MBojowaldBSandhöferASkirzewskiATsobanjan2009Rev. Math. Phys.2111124931141167.8102510.1142/S0129055X09003591Bojowald, M., Sandhöfer, B., Skirzewski, A., Tsobanjan, A.: Rev. Math. Phys. 21, 111 (2009), arXiv:0804.3365 28.JJHalliwellSWHawking1985Phys. Rev. D31817777877481985PhRvD..31.1777H10.1103/PhysRevD.31.1777Halliwell, J.J., Hawking, S.W.: Phys. Rev. D 31(8), 1777 (1985) 29.PDD'Eath2005Supersymmetric Quantum CosmologyCambridge University PressCambridgeD'Eath, P.D.: Supersymmetric Quantum Cosmology. Cambridge University Press, Cambridge (2005) 30.PVMoniz2010Quantum Cosmology - The Supersymmetric PerspectiveSpringerBerlinMoniz, P.V.: Quantum Cosmology—The Supersymmetric Perspective. Springer, Berlin(2010) 31.PDD'EathJJHalliwell1987Phys. Rev. D3511008785261987PhRvD..35.1100D10.1103/PhysRevD.35.1100D'Eath, P.D., Halliwell, J.J.: Phys. Rev. D 35, 1100 (1987) 32.TGold1962Am. J. Phys.304031962AmJPh..30..403G0105.2250110.1119/1.1942052Gold, T.: Am. J. Phys. 30, 403 (1962) 33.SWHawking1985Phys. Rev. D3224898114021985PhRvD..32.2489H10.1103/PhysRevD.32.2489Hawking, S.W.: Phys. Rev. D 32, 2489 (1985) 24.DNPage1985Phys. Rev. D3224968114031985PhRvD..32.2496P10.1103/PhysRevD.32.2496Page, D.N.: Phys. Rev. D 32, 2496 (1985) 35.BCarr2007Universe or Multiverse?Cambridge University PressCambridgeCarr, B.(ed.): Universe or Multiverse? Cambridge University Press, Cambridge (2007) 1.D.GiuliniCKieferE.JoosJKupschI.O.StamatescuH.D.Zeh1996Decoherence and the Appearance of a Classical World in Quantum TheorySpringerBerlin0855.0000310.1007/978-3-662-03263-3Giulini, D., Kiefer, C., Joos, E., Kupsch, J., Stamatescu, I.O., Zeh, H.D.: Decoherence and the Appearance of a Classical World in Quantum Theory. Springer, Berlin (1996) 2.Bojowald, M., Brizuela, D., Hernandez, H.H., Koop, M.J., Morales-Técotl, H.A.:arXiv:1011.3022 3.J.P.GazeauJ.Klauder1999J. Phys. A: Math. Gen.3212316685761999JPhA...32..123G0919.4706110.1088/0305-4470/32/1/013arXiv:1011.3022Gazeau, J.P., Klauder, J.: J. Phys. A: Math. Gen. 32, 123 (1999) 4.M.NovelloS.E.P.Bergliaffa2008Phys. Rep.46312724370502008PhR...463..127N10.1016/j.physrep.2008.04.006Novello, M., Bergliaffa, S.E.P.: Phys. Rep. 463, 127 (2008) 5.M.Bojowald2010Canonical Gravity and Applications: Cosmology, Black Holes, and Quantum GravityCambridge University PressCambridge10.1017/CBO9780511921759Bojowald, M.: Canonical Gravity and Applications: Cosmology, Black Holes, and Quantum Gravity. Cambridge University Press, Cambridge (2010) 6.A.Ashtekar1987Phys. Rev. D36615879096671987PhRvD..36.1587A10.1103/PhysRevD.36.1587Ashtekar, A.: Phys. Rev. D 36(6), 1587 (1987) 7.Barbero G.J.F., (1995) Phys. Rev. D 51(10): 5507 8.G.Immirzi1997Class. Quantum Grav.14L 17714765391997CQGra..14L.177I10.1088/0264-9381/14/10/002Immirzi, G.: Class. Quantum Grav. 14, L 177 (1997) 9.J.LewandowskiE.T.NewmanC.Rovelli1993J. Math. Phys.34464612359631993JMP....34.4646L0790.5305710.1063/1.530362Lewandowski, J., Newman, E.T., Rovelli, C.: J. Math. Phys. 34, 4646 (1993) 10.C.RovelliL.Smolin1990Nucl. Phys. B3318010444931990NuPhB.331...80R10.1016/0550-3213(90)90019-ARovelli, C., Smolin, L.: Nucl. Phys. B 331, 80 (1990) 11.A.CorichiK.Krasnov1998Mod. Phys. Lett. A13133916358811998MPLA...13.1339C10.1142/S0217732398001406hep-th/9703177Corichi, A., Krasnov, K.: Mod. Phys. Lett. A 13, 1339 (1998). hep-th/9703177 12.A.AshtekarJ.LewandowskiD.MarolfJ.Mour aoT.Thiemann1995J. Math. Phys.3611645613559161995JMP....36.6456A0856.5800610.1063/1.531252gr-qc/9504018Ashtekar, A., Lewandowski, J., Marolf, D., Mour ao, J., Thiemann, T.: J. Math. Phys. 36(11), 6456 (1995). gr-qc/9504018 13.A.AshtekarJ.Lewandowski1995J. Math. Phys.365217013292511995JMP....36.2170A0844.5800910.1063/1.531037Ashtekar, A., Lewandowski, J.: J. Math. Phys. 36(5), 2170 (1995) 14.C.RovelliL.Smolin1995Phys. Rev. D5210574313604271995PhRvD..52.5743R10.1103/PhysRevD.52.5743Rovelli, C., Smolin, L.: Phys. Rev. D 52(10), 5743 (1995) 15.C.RovelliL.Smolin1995Nucl. Phys. B44259313327051995NuPhB.442..593R0925.8301310.1016/0550-3213(95)00150-Qgr-qc/9411005, Erratum: Nucl. Phys. B 456 (1995) 753Rovelli, C., Smolin, L.: Nucl. Phys. B 442, 593 (1995). gr-qc/9411005 16.A.AshtekarJ.Lewandowski1997Class Quantum Grav.14A 5516918871997CQGra..14A..55Agr-qc/9602046Ashtekar, A., Lewandowski, J.: Class Quantum Grav. 14, A 55 (1997). gr-qc/9602046 17.A.AshtekarJ.Lewandowski1998Adv. Theor. Math. Phys.13881605640gr-qc/9711031Ashtekar, A., Lewandowski, J.: Adv. Theor. Math. Phys. 1, 388 (1998). gr-qc/9711031 18.R.De PietriC.Rovelli1996Phys. Rev. D544266414069701996PhRvD..54.2664D10.1103/PhysRevD.54.2664De Pietri, R., Rovelli, C.: Phys. Rev. D 54(4), 2664 (1996) 19.J.BrunnemannT.Thiemann2006Class Quantum Grav.23128922054852006CQGra..23.1289B1089.8301310.1088/0264-9381/23/4/014gr-qc/0405060Brunnemann, J., Thiemann, T.: Class Quantum Grav. 23, 1289 (2006). gr-qc/0405060 20.J..BrunnemannD.Rideout2008Class. Quant. Grav.2506500123987022008CQGra..25f5001B10.1088/0264-9381/25/6/065001arXiv:0706.0469Brunnemann, J.., Rideout, D.: Class. Quant. Grav. 25, 065001 (2008). arXiv:0706.0469 21.J.BrunnemannD.Rideout2008Class. Quant. Grav.2506500223987032008CQGra..25f5002B10.1088/0264-9381/25/6/065002arXiv:0706.0382Brunnemann, J., Rideout, D.: Class. Quant. Grav. 25, 065002 (2008). arXiv:0706.0382 22.M.Bojowald2008Living Rev. Relativity1142008LRR....11....4B10.12942/lrr-2008-4gr-qc/0601085, http://www.livingreviews.org/lrr-2008-4Bojowald, M.: Living Rev. Relativity 11, 4 (2008). gr-qc/0601085 23.M.Bojowald2000Class. Quantum Grav.17148917526492000CQGra..17.1489B0969.8303510.1088/0264-9381/17/6/312gr-qc/9910103Bojowald, M.: Class. Quantum Grav. 17, 1489 (2000). gr-qc/9910103 24.M.Bojowald2002Class. Quantum Grav.19271719081252002CQGra..19.2717B1008.8303710.1088/0264-9381/19/10/313gr-qc/0202077Bojowald, M.: Class. Quantum Grav. 19, 2717 (2002). gr-qc/0202077 25.C.FewsterH.Sahlmann2008Class Quantum Grav2522501524533882008CQGra..25v5015F10.1088/0264-9381/25/22/225015arXiv:0804.2541Fewster, C., Sahlmann, H.: Class Quantum Grav 25, 225015 (2008). arXiv:0804.2541 26.J.M.Velhinho2007Class. Quantum Grav.24374523394202007CQGra..24.3745V1129.8332410.1088/0264-9381/24/14/013arXiv:0704.2397.Velhinho, J.M.: Class. Quantum Grav. 24, 3745 (2007). arXiv:0704.2397. 27.TThiemann1998Class Quantum Grav1583916202091998CQGra..15..839T0956.8301310.1088/0264-9381/15/4/011gr-qc/9606089Thiemann, T.: Class Quantum Grav 15, 839 (1998). gr-qc/9606089 28.T.Thiemann1998Class. Quantum Grav.15128116230751998CQGra..15.1281T0945.8301610.1088/0264-9381/15/5/012gr-qc/9705019Thiemann, T.: Class. Quantum Grav. 15, 1281 (1998). gr-qc/9705019 29.M.Bojowald2001Phys. Rev. D6408401818587272001PhRvD..64h4018B10.1103/PhysRevD.64.084018gr-qc/0105067Bojowald, M.: Phys. Rev. D 64, 084018 (2001). gr-qc/0105067 30.J.BrunnemannT.Thiemann2006Class. Quantum Grav.23139522046892006CQGra..23.1395B1097.8301310.1088/0264-9381/23/5/001gr-qc/0505032Brunnemann, J., Thiemann, T.: Class. Quantum Grav. 23, 1395 (2006). gr-qc/0505032 31.M.Bojowald2006Class. Quantum Grav.2398722029402006CQGra..23..987B1087.8302710.1088/0264-9381/23/3/023gr-qc/0508118Bojowald, M.: Class. Quantum Grav. 23, 987 (2006). gr-qc/0508118 32.J.BrunnemannT.Thiemann2006Class. Quantum Grav.23142922046902006CQGra..23.1429B1089.8301410.1088/0264-9381/23/5/002gr-qc/0505033Brunnemann, J., Thiemann, T.: Class. Quantum Grav. 23, 1429 (2006). gr-qc/0505033 1.W.Unruh1997Time, Gravity, and Quantum MechanicsCambridge University PressCambridge2394Unruh, W.: Time, Gravity, and Quantum Mechanics pp. 23-94. Cambridge University Press, Cambridge (1997) 2.N.Weiss1985Phys Rev D3232288150791985PhRvD..32.3228W10.1103/PhysRevD.32.3228Weiss, N.: Phys. Rev. D 32, 3228 (1985) 3.Jacobson, T.: (2000). hep-th/0001085 4.M.BojowaldP.SinghA.Skirzewski2004Phys. Rev. D7012402221247062004PhRvD..70l4022B10.1103/PhysRevD.70.124022gr-qc/0408094Bojowald, M., Singh, P., Skirzewski, A.: Phys. Rev. D 70, 124022 (2004). gr-qc/0408094 5.C.RovelliL.Smolin1994Phys. Rev. Lett.7244612569161994PhRvL..72..446R0973.8352310.1103/PhysRevLett.72.446gr-qc/9308002Rovelli, C., Smolin, L.: Phys. Rev. Lett. 72, 446 (1994). gr-qc/9308002 6.K.GieselT.Thiemann2007Class Quantum Grav.24246523194272007CQGra..24.2465G1117.8304510.1088/0264-9381/24/10/003gr-qc/0607099Giesel, K., Thiemann, T.: Class Quantum Grav. 24, 2465 (2007). gr-qc/0607099 7.T.Thiemann1998Class Quantum Grav.1583916202091998CQGra..15..839T0956.8301310.1088/0264-9381/15/4/011gr-qc/9606089Thiemann, T.: Class Quantum Grav. 15, 839 (1998). gr-qc/9606089 8.T.Thiemann1998Class Quantum Grav.15128116230751998CQGra..15.1281T0945.8301610.1088/0264-9381/15/5/012gr-qc/9705019Thiemann, T.: Class Quantum Grav. 15, 1281 (1998). gr-qc/9705019 9.T.Thiemann1998Class Quantum Grav.1587516202131998CQGra..15..875T10.1088/0264-9381/15/4/012gr-qc/9606090Thiemann, T.: Class Quantum Grav. 15, 875 (1998). gr-qc/9606090 10.T.Thiemann1996Phys. Lett. B38025713983881996PhLB..380..257T0945.8301310.1016/0370-2693(96)00532-1gr-qc/9606088Thiemann, T.: Phys. Lett. B 380, 257 (1996). gr-qc/9606088 11.J.LewandowskiD.Marolf1998Int. J. Mod. Phys. D729916357561998IJMPD...7..299L0936.8302210.1142/S0218271898000231gr-qc/9710016Lewandowski, J., Marolf, D.: Int. J Mod. Phys. D 7, 299 (1998). gr-qc/9710016 12.R.GambiniJ.LewandowskiD.MarolfJ.Pullin1998Int. J Mod. Phys. D79716250591998IJMPD...7...97G0936.8302110.1142/S0218271898000103gr-qc/9710018Gambini, R., Lewandowski, J., Marolf, D., Pullin, J.: Int. J Mod. Phys. D 7, 97 (1998).gr-qc/9710018 13.A.AshtekarJ.LewandowskiH.Sahlmann2003Class Quantum Grav.20L1119557752003CQGra..20L..11A1025.8350110.1088/0264-9381/20/1/103gr-qc/0211012Ashtekar, A., Lewandowski, J., Sahlmann, H.: Class Quantum Grav. 20, L11 (2003). gr-qc/0211012 14.H.SahlmannT.Thiemann2006Class Quantum Grav.2386722029362006CQGra..23..867S1098.8301410.1088/0264-9381/23/3/019gr-qc/0207030Sahlmann, H., Thiemann, T.: Class Quantum Grav. 23, 867 (2006). gr-qc/0207030 15.M.Bojowald2009

Improving management performance of P2PSIP for mobile sensing in wireless overlays.

PubMed

Sendín-Raña, Pablo; González-Castaño, Francisco Javier; Gómez-Cuba, Felipe; Asorey-Cacheda, Rafael; Pousada-Carballo, José María

2013-11-08

Future wireless communications are heading towards an all-Internet Protocol (all-IP) design, and will rely on the Session Initiation Protocol (SIP) to manage services, such as voice over IP (VoIP). The centralized architecture of traditional SIP has numerous disadvantages for mobile ad hoc services that may be possibly overcome by advanced peer-to-peer (P2P) technologies initially developed for the Internet. In the context of mobile sensing, P2PSIP protocols facilitate decentralized and fast communications with sensor-enabled terminals. Nevertheless, in order to make P2PSIP protocols feasible in mobile sensing networks, it is necessary to minimize overhead transmissions for signaling purposes, which reduces the battery lifetime. In this paper, we present a solution to improve the management of wireless overlay networks by defining an adaptive algorithm for the calculation of refresh time. The main advantage of the proposed algorithm is that it takes into account new parameters, such as the delay between nodes, and provides satisfactory performance and reliability levels at a much lower management overhead than previous approaches. The proposed solution can be applied to many structured P2P overlays or P2PSIP protocols. We evaluate it with Kademlia-based distributed hash tables (DHT) and dSIP.

Improving Management Performance of P2PSIP for Mobile Sensing in Wireless Overlays

PubMed Central

Sendín-Raña, Pablo; González-Castaño, Francisco Javier; Gómez-Cuba, Felipe; Asorey-Cacheda, Rafael; Pousada-Carballo, José María

2013-01-01

Future wireless communications are heading towards an all-Internet Protocol (all-IP) design, and will rely on the Session Initiation Protocol (SIP) to manage services, such as voice over IP (VoIP). The centralized architecture of traditional SIP has numerous disadvantages for mobile ad hoc services that may be possibly overcome by advanced peer-to-peer (P2P) technologies initially developed for the Internet. In the context of mobile sensing, P2PSIP protocols facilitate decentralized and fast communications with sensor-enabled terminals. Nevertheless, in order to make P2PSIP protocols feasible in mobile sensing networks, it is necessary to minimize overhead transmissions for signaling purposes, which reduces the battery lifetime. In this paper, we present a solution to improve the management of wireless overlay networks by defining an adaptive algorithm for the calculation of refresh time. The main advantage of the proposed algorithm is that it takes into account new parameters, such as the delay between nodes, and provides satisfactory performance and reliability levels at a much lower management overhead than previous approaches. The proposed solution can be applied to many structured P2P overlays or P2PSIP protocols. We evaluate it with Kademlia-based distributed hash tables (DHT) and dSIP PMID:24217358

Transient bleaching of small PbS colloids. Influence of surface properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nenadovic, M.T.; Comor, M.I.; Vasic, V.

1990-08-09

Small PbS colloids with a particle diameter of 40 {angstrom} were prepared in aqueous solution, and their absorption spectra exhibit several maxima. Injection of electrons into these particles was achieved by using the pulse radiolysis technique. Excess electrons trapped on the surface lead to a blue shift in the absorption edge of colloids. The appearance of this shift depends critically on the method of colloid preparation. PbS and CdS colloids prepared at pH < 6 have long-lived bleaching, which disappears after several seconds. On the other hand, absorption bleaching does not appear after the addition of hydroxide ions to colloidalmore » solutions (pH > 8). The existence of a hydroxide ion on the particle surface most likely removes surface defects on which electrons are trapped. PbS colloids prepared in the presence of 3-mercapto-1,2-propanediol have an unstructured absorption spectrum, which is due to a wide particle size distribution (10-50 {angstrom}).« less

Big Data, Predictive Analytics, and Quality Improvement in Kidney Transplantation: A Proof of Concept.

PubMed

Srinivas, T R; Taber, D J; Su, Z; Zhang, J; Mour, G; Northrup, D; Tripathi, A; Marsden, J E; Moran, W P; Mauldin, P D

2017-03-01

We sought proof of concept of a Big Data Solution incorporating longitudinal structured and unstructured patient-level data from electronic health records (EHR) to predict graft loss (GL) and mortality. For a quality improvement initiative, GL and mortality prediction models were constructed using baseline and follow-up data (0-90 days posttransplant; structured and unstructured for 1-year models; data up to 1 year for 3-year models) on adult solitary kidney transplant recipients transplanted during 2007-2015 as follows: Model 1: United Network for Organ Sharing (UNOS) data; Model 2: UNOS & Transplant Database (Tx Database) data; Model 3: UNOS, Tx Database & EHR comorbidity data; and Model 4: UNOS, Tx Database, EHR data, Posttransplant trajectory data, and unstructured data. A 10% 3-year GL rate was observed among 891 patients (2007-2015). Layering of data sources improved model performance; Model 1: area under the curve (AUC), 0.66; (95% confidence interval [CI]: 0.60, 0.72); Model 2: AUC, 0.68; (95% CI: 0.61-0.74); Model 3: AUC, 0.72; (95% CI: 0.66-077); Model 4: AUC, 0.84, (95 % CI: 0.79-0.89). One-year GL (AUC, 0.87; Model 4) and 3-year mortality (AUC, 0.84; Model 4) models performed similarly. A Big Data approach significantly adds efficacy to GL and mortality prediction models and is EHR deployable to optimize outcomes. © 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.

Resource Management In Peer-To-Peer Networks: A Nadse Approach

NASA Astrophysics Data System (ADS)

Patel, R. B.; Garg, Vishal

2011-12-01

This article presents a common solution to Peer-to-Peer (P2P) network problems and distributed computing with the help of "Neighbor Assisted Distributed and Scalable Environment" (NADSE). NADSE supports both device and code mobility. In this article mainly we focus on the NADSE based resource management technique. How information dissemination and searching is speedup when using the NADSE service provider node in large network. Results show that performance of the NADSE network is better in comparison to Gnutella, and Freenet.

MATIN: A Random Network Coding Based Framework for High Quality Peer-to-Peer Live Video Streaming

PubMed Central

Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Triviño

2013-01-01

In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay. PMID:23940530

Three cobalt(II)-linked {P8W48} network assemblies: syntheses, structures, and magnetic and photocatalysis properties.

PubMed

Jiao, Yan-Qing; Qin, Chao; Wang, Xin-Long; Wang, Chun-Gang; Sun, Chun-Yi; Wang, Hai-Ning; Shao, Kui-Zhan; Su, Zhong-Min

2014-02-01

Three cobalt(II)-containing tungstophosphate compounds, Na8Li8Co5[Co5.5(H2O)19P8W48.5O184]⋅60 H2O (1), K2Na4Li11Co5[Co7(H2O)28P8W48O184]Cl⋅ 59 H2O (2), and K2Na4LiCo11[Co8(H2O)32P8W48O184](CH3COO)4Cl⋅47 H2O (3), have been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, elemental analyses, and magnetic measurements. The pH value impacts the formation of distinct cobalt-linked frameworks. The cyclic cavity of the polyanion accommodates 5.5, 7, and 8 cobalt ions in 1, 2, and 3, respectively. In compounds 1 and 2, each {Co5.5P8W48} and {Co7P8W48} fragment links to four others through multiple {Co-O-W} coordination bonds to generate a two-dimensional network. Compound 3 can be considered as a 3D network based on the {Co-O-W} coordination bonds and the {Co3(CH3COO)2(H2O)10} linkers between the {P8W48} fragments. Interestingly, acetate ligands have been employed to form the {Co3(CH3COO)2(H2O)10} unit, thereby inducing the construction of a 12-connected framework. To the best of our knowledge, compound 3 contains the largest-ever number of cobalt ions in a {P8W48}-based polyoxometalate when counterions are taken into account and the {P8W48} unit shows the highest number of connections thanks to the carboxyl bridges. The UV/Vis diffuse reflectance spectra of these powder samples indicate that the corresponding well-defined optical absorption associated with Eg can be assessed at 2.58, 2.48, and 2.73 eV and reveal the presence of an optical band gap. The photocatalytic H2 evolution activities of these {P8W48}-based compounds are evaluated. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distributed network management in the flat structured mobile communities

NASA Astrophysics Data System (ADS)

Balandina, Elena

2005-10-01

Delivering proper management into the flat structured mobile communities is crucial for improving users experience and increase applications diversity in mobile networks. The available P2P applications do application-centric management, but it cannot replace network-wide management, especially when a number of different applications are used simultaneously in the network. The network-wide management is the key element required for a smooth transition from standalone P2P applications to the self-organizing mobile communities that maintain various services with quality and security guaranties. The classical centralized network management solutions are not applicable in the flat structured mobile communities due to the decentralized nature and high mobility of the underlying networks. Also the basic network management tasks have to be revised taking into account specialties of the flat structured mobile communities. The network performance management becomes more dependent on the current nodes' context, which also requires extension of the configuration management functionality. The fault management has to take into account high mobility of the network nodes. The performance and accounting managements are mainly targeted in maintain an efficient and fair access to the resources within the community, however they also allow unbalanced resource use of the nodes that explicitly permit it, e.g. as a voluntary donation to the community or due to the profession (commercial) reasons. The security management must implement the new trust models, which are based on the community feedback, professional authorization, and a mix of both. For fulfilling these and another specialties of the flat structured mobile communities, a new network management solution is demanded. The paper presents a distributed network management solution for flat structured mobile communities. Also the paper points out possible network management roles for the different parties (e.g. operators, service providing hubs/super nodes, etc.) involved in a service providing chain.

Using peer-to-peer energy-trading platforms to incentivize prosumers to form federated power plants

NASA Astrophysics Data System (ADS)

Morstyn, Thomas; Farrell, Niall; Darby, Sarah J.; McCulloch, Malcolm D.

2018-02-01

Power networks are undergoing a fundamental transition, with traditionally passive consumers becoming `prosumers' — proactive consumers with distributed energy resources, actively managing their consumption, production and storage of energy. A key question that remains unresolved is: how can we incentivize coordination between vast numbers of distributed energy resources, each with different owners and characteristics? Virtual power plants and peer-to-peer (P2P) energy trading offer different sources of value to prosumers and the power network, and have been proposed as different potential structures for future prosumer electricity markets. In this Perspective, we argue they can be combined to capture the benefits of both. We thus propose the concept of the federated power plant, a virtual power plant formed through P2P transactions between self-organizing prosumers. This addresses social, institutional and economic issues faced by top-down strategies for coordinating virtual power plants, while unlocking additional value for P2P energy trading.

Surgical Crisis Management Skills Training and Assessment

PubMed Central

Moorthy, Krishna; Munz, Yaron; Forrest, Damien; Pandey, Vikas; Undre, Shabnam; Vincent, Charles; Darzi, Ara

2006-01-01

Background: Intraoperative surgical crisis management is learned in an unstructured manner. In aviation, simulation training allows aircrews to coordinate and standardize recovery strategies. Our aim was to develop a surgical crisis simulation and evaluate its feasibility, realism, and validity of the measures used to assess performance. Methods: Surgical trainees were exposed to a bleeding crisis in a simulated operating theater. Assessment of performance consisted of a trainee’s technical ability to control the bleeding and of their team/human factors skills. This assessment was performed in a blinded manner by 2 surgeons and one human factors expert. Other measures consisted of time measures such as time to diagnose the bleeding (TD), inform team members (TT), achieve control (TC), and close the laceration (TL). Blood loss was used as a surrogate outcome measures. Results: There were considerable variations within both senior (n = 10) and junior (n = 10) trainees for technical and team skills. However, while the senior trainees scored higher than the juniors for technical skills (P = 0.001), there were no differences in human factors skills. There were also significant differences between the 2 groups for TD (P = 0.01), TC (P = 0.001), and TL (0.001). The blood loss was higher in the junior group. Conclusions: We have described the development of a novel simulated setting for the training of crisis management skills and the variability in performance both in between and within the 2 groups. PMID:16794399

Genome-wide association study of rust traits in orchardgrass using SLAF-seq technology.

PubMed

Zeng, Bing; Yan, Haidong; Liu, Xinchun; Zang, Wenjing; Zhang, Ailing; Zhou, Sifan; Huang, Linkai; Liu, Jinping

2017-01-01

While orchardgrass ( Dactylis glomerata L.) is a well-known perennial forage species, rust diseases cause serious reductions in the yield and quality of orchardgrass; however, genetic mechanisms of rust resistance are not well understood in orchardgrass. In this study, a genome-wide association study (GWAS) was performed using specific-locus amplified fragment sequencing (SLAF-seq) technology in orchardgrass. A total of 2,334,889 SLAF tags were generated to produce 2,309,777 SNPs. ADMIXTURE analysis revealed unstructured subpopulations for 33 accessions, indicating that this orchardgrass population could be used for association analysis. Linkage disequilibrium (LD) analysis revealed an average r 2 of 0.4 across all SNP pairs, indicating a high extent of LD in these samples. Through GWAS, a total of 4,604 SNPs were found to be significantly ( P  < 0.01) associated with the rust trait. The bulk analysis discovered a number of 5,211 SNPs related to rust trait. Two candidate genes, including cytochrome P450, and prolamin were implicated in disease resistance through prediction of functional genes surrounding each high-quality SNP ( P  < 0.01) associated with rust traits based on GWAS analysis and bulk analysis. The large number of SNPs associated with rust traits and these two candidate genes may provide the basis for further research on rust resistance mechanisms and marker-assisted selection (MAS) for rust-resistant lineages.

Stimulated Emission Depletion Live-Cell Super-Resolution Imaging Shows Proliferative Remodeling of T-Tubule Membrane Structures After Myocardial Infarction

PubMed Central

Wagner, Eva; Lauterbach, Marcel A.; Kohl, Tobias; Westphal, Volker; Williams, George S.B.; Steinbrecher, Julia H.; Streich, Jan-Hendrik; Korff, Brigitte; Tuan, Hoang-Trong M.; Hagen, Brian; Luther, Stefan; Hasenfuss, Gerd; Parlitz, Ulrich; Jafri, M. Saleet; Hell, Stefan W.; Lederer, W. Jonathan; Lehnart, Stephan E.

2014-01-01

Rationale Transverse tubules (TTs) couple electric surface signals to remote intracellular Ca2+ release units (CRUs). Diffraction-limited imaging studies have proposed loss of TT components as disease mechanism in heart failure (HF). Objectives Objectives were to develop quantitative super-resolution strategies for live-cell imaging of TT membranes in intact cardiomyocytes and to show that TT structures are progressively remodeled during HF development, causing early CRU dysfunction. Methods and Results Using stimulated emission depletion (STED) microscopy, we characterized individual TTs with nanometric resolution as direct readout of local membrane morphology 4 and 8 weeks after myocardial infarction (4pMI and 8pMI). Both individual and network TT properties were investigated by quantitative image analysis. The mean area of TT cross sections increased progressively from 4pMI to 8pMI. Unexpectedly, intact TT networks showed differential changes. Longitudinal and oblique TTs were significantly increased at 4pMI, whereas transversal components appeared decreased. Expression of TT-associated proteins junctophilin-2 and caveolin-3 was significantly changed, correlating with network component remodeling. Computational modeling of spatial changes in HF through heterogeneous TT reorganization and RyR2 orphaning (5000 of 20 000 CRUs) uncovered a local mechanism of delayed subcellular Ca2+ release and action potential prolongation. Conclusions This study introduces STED nanoscopy for live mapping of TT membrane structures. During early HF development, the local TT morphology and associated proteins were significantly altered, leading to differential network remodeling and Ca2+ release dyssynchrony. Our data suggest that TT remodeling during HF development involves proliferative membrane changes, early excitation-contraction uncoupling, and network fracturing. PMID:22723297

Medium-Range Structural Organization of Phosphorus-Bearing Borosilicate Glasses Revealed by Advanced Solid-State NMR Experiments and MD Simulations: Consequences of B/Si Substitutions.

PubMed

Yu, Yang; Stevensson, Baltzar; Edén, Mattias

2017-10-19

The short and intermediate range structures of a large series of bioactive borophosphosilicate (BPS) glasses were probed by solid-state nuclear magnetic resonance (NMR) spectroscopy and atomistic molecular dynamics (MD) simulations. Two BPS glass series were designed by gradually substituting SiO 2 by B 2 O 3 in the respective phosphosilicate base compositions 24.1Na 2 O-23.3CaO-48.6SiO 2 -4.0P 2 O 5 ("S49") and 24.6Na 2 O-26.7CaO-46.1SiO 2 -2.6P 2 O 5 ("S46"), the latter constituting the "45S5 Bioglass" utilized for bone grafting applications. The BPS glass networks are built by interconnected SiO 4 , BO 4 , and BO 3 moieties, whereas P exists mainly as orthophosphate anions, except for a minor network-associated portion involving P-O-Si and P-O-B [4] motifs, whose populations were estimated by heteronuclear 31 P{ 11 B} NMR experimentation. The high Na + /Ca 2+ contents give fragmented glass networks with large amounts of nonbridging oxygen (NBO) anions. The MD-generated glass models reveal an increasing propensity for NBO accommodation among the network units according to BO 4 < SiO 4 < BO 3 ≪ PO 4 . The BO 4 /BO 3 intermixing was examined by double-quantum-single-quantum correlation 11 B NMR experiments, which evidenced the presence of all three BO 3 -BO 3 , BO 3 -BO 4 , and BO 4 -BO 4 connectivities, with B [3] -O-B [4] bridges dominating. Notwithstanding that B [4] -O-B [4] linkages are disfavored, both NMR spectroscopy and MD simulations established their presence in these modifier-rich BPS glasses, along with non-negligible B [4] -NBO contacts, at odds with the conventional structural view of borosilicate glasses. We discuss the relative propensities for intermixing of the Si/B/P network formers. Despite the absence of pronounced preferences for Si-O-Si bond formation, the glass models manifest subtle subnanometer-sized structural inhomogeneities, where SiO 4 tetrahedra tend to self-associate into small chain/ring motifs embedded in BO 3 /BO 4 -dominated domains.

The impact of a social network intervention on retention in Belgian therapeutic communities: a quasi-experimental study.

PubMed

Soyez, Veerle; De Leon, George; Broekaert, Eric; Rosseel, Yves

2006-07-01

Although numerous studies recognize the importance of social network support in engaging substance abusers into treatment, there is only limited knowledge of the impact of network involvement and support during treatment. The primary objective of this research was to enhance retention in Therapeutic Community treatment utilizing a social network intervention. The specific goals of this study were (1) to determine whether different pre-treatment factors predicted treatment retention in a Therapeutic Community; and (2) to determine whether participation of significant others in a social network intervention predicted treatment retention. Consecutive admissions to four long-term residential Therapeutic Communities were assessed at intake (n = 207); the study comprised a mainly male (84.9%) sample of polydrug (41.1%) and opiate (20.8%) abusers, of whom 64.4% had ever injected drugs. Assessment involved the European version of the Addiction Severity Index (EuropASI), the Circumstances, Motivation, Readiness scales (CMR), the Dutch version of the family environment scale (GKS/FES) and an in-depth interview on social network structure and perceived social support. Network members of different cohorts were assigned to a social network intervention, which consisted of three elements (a video, participation at an induction day and participation in a discussion session). Hierarchical regression analyses showed that client-perceived social support (F1,198 = 10.9, P = 0.001) and treatment motivation and readiness (F1,198 = 8.8; P = 0.003) explained a significant proportion of the variance in treatment retention (model fit: F7,197 = 4.4; P = 0.000). By including the variable 'significant others' participation in network intervention' (network involvement) in the model, the fit clearly improved (F1,197 = 6.2; P = 0.013). At the same time, the impact of perceived social support decreased (F1,197 = 2.9; P = 0.091). Participation in the social network intervention was associated with improved treatment retention controlling for other client characteristics. This suggests that the intervention may be of benefit in the treatment of addicted individuals.

State of the art in electromagnetic modeling for the Compact Linear Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candel, Arno; Kabel, Andreas; Lee, Lie-Quan

SLAC's Advanced Computations Department (ACD) has developed the parallel 3D electromagnetic time-domain code T3P for simulations of wakefields and transients in complex accelerator structures. T3P is based on state-of-the-art Finite Element methods on unstructured grids and features unconditional stability, quadratic surface approximation and up to 6th-order vector basis functions for unprecedented simulation accuracy. Optimized for large-scale parallel processing on leadership supercomputing facilities, T3P allows simulations of realistic 3D structures with fast turn-around times, aiding the design of the next generation of accelerator facilities. Applications include simulations of the proposed two-beam accelerator structures for the Compact Linear Collider (CLIC) - wakefieldmore » damping in the Power Extraction and Transfer Structure (PETS) and power transfer to the main beam accelerating structures are investigated.« less

Continuous pCO2 time series from Ocean Networks Canada cabled observatories at the northeast Pacific shelf edge and in the sub-tidal Arctic

NASA Astrophysics Data System (ADS)

Juniper, S. Kim; Sastri, Akash; Mihaly, Steven; Duke, Patrick; Else, Brent; Thomas, Helmuth; Miller, Lisa

2017-04-01

Marine pCO2 sensor technology has progressed to the point where months-long time series from remotely-deployed pCO2 sensors can be used to document seasonal and higher frequency variability in pCO2 and its relationship to oceanographic processes. Ocean Networks Canada recently deployed pCO2 sensors on two cabled platforms: a bottom-moored (400 m depth), vertical profiler at the edge of the northeast Pacific continental shelf off Vancouver Island, Canada, and a subtidal seafloor platform in the Canadian High Arctic (69˚ N) at Cambridge Bay, Nunavut. Both platforms streamed continuous data to a shore-based archive from Pro-Oceanus pCO2 sensors and other oceanographic instruments. The vertical profiler time series revealed substantial intrusions of corrosive (high CO2/low O2), saltier, colder water masses during the summertime upwelling season and during winter-time reversals of along-slope currents. Step-wise profiles during the downcast provided the most reliable pCO2 data, permitting the sensor to equilibrate to the broad range of pCO2 concentrations encountered over the 400 metre depth interval. The Arctic pCO2 sensor was deployed in August 2015. Reversing seasonal trends in pCO2 and dissolved oxygen values can be related to the changing balance of photosynthesis and respiration under sea ice, as influenced by irradiance. Correlation of pCO2 and dissolved oxygen sensor data and the collection of calibration samples have permitted evaluation of sensor performance in relation to operational conditions encountered in vertical profiling and lengthy exposure to subzero seawater.

Special Course on Unstructured Grid Methods for Advection Dominated Flows (Les Methodes Utilisant un Maillage non Structure Pour l’Etude des Ecoulements Caracterises par l’Advection)

DTIC Science & Technology

1992-05-01

gvfl.nds. where [ý nS.VUJ denotes the jump in the F quantity • ns.VU across a triangle side S where b and i are defined by (1.11) with (in the interior of...error estimate for (1.12) recalling that i = (2.1b) u = 0o n P ,x I, max(C 2 hR(U)/ I VU I , h3/2): (2.Ic) u(.,0) u in le, ’ Theorem 1.1. There is a...8217"..< tn <"" tN -= IF be a sequence of discrete time levels, set We note that by (I. 16d) the quantity I/ = (tni, t.n+1 ), k1 = t+ I - t.n and E(h,U,f

The use of artificial neural network (ANN) for the prediction and simulation of oil degradation in wastewater by AOP.

PubMed

Mustafa, Yasmen A; Jaid, Ghydaa M; Alwared, Abeer I; Ebrahim, Mothana

2014-06-01

The application of advanced oxidation process (AOP) in the treatment of wastewater contaminated with oil was investigated in this study. The AOP investigated is the homogeneous photo-Fenton (UV/H2O2/Fe(+2)) process. The reaction is influenced by the input concentration of hydrogen peroxide H2O2, amount of the iron catalyst Fe(+2), pH, temperature, irradiation time, and concentration of oil in the wastewater. The removal efficiency for the used system at the optimal operational parameters (H2O2 = 400 mg/L, Fe(+2) = 40 mg/L, pH = 3, irradiation time = 150 min, and temperature = 30 °C) for 1,000 mg/L oil load was found to be 72%. The study examined the implementation of artificial neural network (ANN) for the prediction and simulation of oil degradation in aqueous solution by photo-Fenton process. The multilayered feed-forward networks were trained by using a backpropagation algorithm; a three-layer network with 22 neurons in the hidden layer gave optimal results. The results show that the ANN model can predict the experimental results with high correlation coefficient (R (2) = 0.9949). The sensitivity analysis showed that all studied variables (H2O2, Fe(+2), pH, irradiation time, temperature, and oil concentration) have strong effect on the oil degradation. The pH was found to be the most influential parameter with relative importance of 20.6%.

Survey of Knowledge Representation and Reasoning Systems

DTIC Science & Technology

2009-07-01

processing large volumes of unstructured information such as natural language documents, email, audio , images and video [Ferrucci et al. 2006]. Using this...information we hope to obtain improved es- timation and prediction, data-mining, social network analysis, and semantic search and visualisation . Knowledge

Evolution of SH2 domains and phosphotyrosine signalling networks

PubMed Central

Liu, Bernard A.; Nash, Piers D.

2012-01-01

Src homology 2 (SH2) domains mediate selective protein–protein interactions with tyrosine phosphorylated proteins, and in doing so define specificity of phosphotyrosine (pTyr) signalling networks. SH2 domains and protein-tyrosine phosphatases expand alongside protein-tyrosine kinases (PTKs) to coordinate cellular and organismal complexity in the evolution of the unikont branch of the eukaryotes. Examination of conserved families of PTKs and SH2 domain proteins provides fiduciary marks that trace the evolutionary landscape for the development of complex cellular systems in the proto-metazoan and metazoan lineages. The evolutionary provenance of conserved SH2 and PTK families reveals the mechanisms by which diversity is achieved through adaptations in tissue-specific gene transcription, altered ligand binding, insertions of linear motifs and the gain or loss of domains following gene duplication. We discuss mechanisms by which pTyr-mediated signalling networks evolve through the development of novel and expanded families of SH2 domain proteins and the elaboration of connections between pTyr-signalling proteins. These changes underlie the variety of general and specific signalling networks that give rise to tissue-specific functions and increasingly complex developmental programmes. Examination of SH2 domains from an evolutionary perspective provides insight into the process by which evolutionary expansion and modification of molecular protein interaction domain proteins permits the development of novel protein-interaction networks and accommodates adaptation of signalling networks. PMID:22889907

P2S--Coupled simulation with the Precipitation-Runoff Modeling System (PRMS) and the Stream Temperature Network (SNTemp) Models

USGS Publications Warehouse

Markstrom, Steven L.

2012-01-01

A software program, called P2S, has been developed which couples the daily stream temperature simulation capabilities of the U.S. Geological Survey Stream Network Temperature model with the watershed hydrology simulation capabilities of the U.S. Geological Survey Precipitation-Runoff Modeling System. The Precipitation-Runoff Modeling System is a modular, deterministic, distributed-parameter, physical-process watershed model that simulates hydrologic response to various combinations of climate and land use. Stream Network Temperature was developed to help aquatic biologists and engineers predict the effects of changes that hydrology and energy have on water temperatures. P2S will allow scientists and watershed managers to evaluate the effects of historical climate and projected climate change, landscape evolution, and resource management scenarios on watershed hydrology and in-stream water temperature.

A Strategy Based on Protein-Protein Interface Motifs May Help in Identifying Drug Off-Targets

PubMed Central

Engin, H. Billur; Keskin, Ozlem; Nussinov, Ruth; Gursoy, Attila

2014-01-01

Networks are increasingly used to study the impact of drugs at the systems level. From the algorithmic standpoint, a drug can ‘attack’ nodes or edges of a protein-protein interaction network. In this work, we propose a new network strategy, “The Interface Attack”, based on protein-protein interfaces. Similar interface architectures can occur between unrelated proteins. Consequently, in principle, a drug that binds to one has a certain probability of binding others. The interface attack strategy simultaneously removes from the network all interactions that consist of similar interface motifs. This strategy is inspired by network pharmacology and allows inferring potential off-targets. We introduce a network model which we call “Protein Interface and Interaction Network (P2IN)”, which is the integration of protein-protein interface structures and protein interaction networks. This interface-based network organization clarifies which protein pairs have structurally similar interfaces, and which proteins may compete to bind the same surface region. We built the P2IN of p53 signaling network and performed network robustness analysis. We show that (1) ‘hitting’ frequent interfaces (a set of edges distributed around the network) might be as destructive as eleminating high degree proteins (hub nodes); (2) frequent interfaces are not always topologically critical elements in the network; and (3) interface attack may reveal functional changes in the system better than attack of single proteins. In the off-target detection case study, we found that drugs blocking the interface between CDK6 and CDKN2D may also affect the interaction between CDK4 and CDKN2D. PMID:22817115

Status of anesthesiology resident research education in the United States: structured education programs increase resident research productivity.

PubMed

Ahmad, Shireen; De Oliveira, Gildasio S; McCarthy, Robert J

2013-01-01

The enhancement of resident research education has been proposed to increase the number of academic anesthesiologists with the skills and knowledge to conduct meaningful research. Program directors (PDs) of the U.S. anesthesiology residency programs were surveyed to evaluate the status of research education during residency training and to test the hypothesis that structured programs result in greater resident research productivity based on resident publications. Survey responses were solicited from 131 anesthesiology residency PDs. Seventy-four percent of PDs responded to the survey. Questions evaluated department demographic information, the extent of faculty research activity, research resources and research funding in the department, the characteristics of resident research education and resident research productivity, departmental support for resident research, and perceived barriers to resident research education. Thirty-two percent of programs had a structured resident research education program. Structured programs were more likely to be curriculum based, require resident participation in a research project, and provide specific training in presentation and writing skills. Productivity expectations were similar between structured and nonstructured programs. Forty percent of structured programs had > 20% of trainees with a publication in the last 2 years compared with 14% of departments with unstructured programs (difference, 26%; 99% confidence interval [CI], 8%-51%; P = 0.01). The percentage of programs that had research rotations for ≥2 months was not different between the structured and the nonstructured programs. A research rotation of >2 months did not increase the percentage of residents who had published an article within the last 2 months compared with a research rotation of <2 months (difference, 13%; 99% CI, 10%-37%; P = 0.14). There was no difference in the percentage of faculty involved in research in structured compared with unstructured research education. In programs with <20% of faculty involved in research, 15% reported >20% of residents with a publication in the last 2 years compared with 36% in programs with >20% of faculty involvement (difference, 21%; 99% CI, -4% to 46%; P = 0.03). Our findings suggest that structured residency research programs are associated with higher resident research productivity. The program duration and the fraction of faculty in resident research education did not significantly increase research productivity. Research training is an integral component of resident education, but the mandatory enhancement of resident research education will require a significant change in the culture of academic anesthesiology leadership and faculty.

SAXS analysis of single- and multi-core iron oxide magnetic nanoparticles

PubMed Central

Szczerba, Wojciech; Costo, Rocio; Morales, Maria del Puerto; Thünemann, Andreas F.

2017-01-01

This article reports on the characterization of four superparamagnetic iron oxide nanoparticles stabilized with dimercaptosuccinic acid, which are suitable candidates for reference materials for magnetic properties. Particles p1 and p2 are single-core particles, while p3 and p4 are multi-core particles. Small-angle X-ray scattering analysis reveals a lognormal type of size distribution for the iron oxide cores of the particles. Their mean radii are 6.9 nm (p1), 10.6 nm (p2), 5.5 nm (p3) and 4.1 nm (p4), with narrow relative distribution widths of 0.08, 0.13, 0.08 and 0.12. The cores are arranged as a clustered network in the form of dense mass fractals with a fractal dimension of 2.9 in the multi-core particles p3 and p4, but the cores are well separated from each other by a protecting organic shell. The radii of gyration of the mass fractals are 48 and 44 nm, and each network contains 117 and 186 primary particles, respectively. The radius distributions of the primary particle were confirmed with transmission electron microscopy. All particles contain purely maghemite, as shown by X-ray absorption fine structure spectroscopy. PMID:28381973

Off-great-circle paths in transequatorial propagation: 2. Nonmagnetic-field-aligned reflections

NASA Astrophysics Data System (ADS)

Tsunoda, Roland T.; Maruyama, Takashi; Tsugawa, Takuya; Yokoyama, Tatsuhiro; Ishii, Mamoru; Nguyen, Trang T.; Ogawa, Tadahiko; Nishioka, Michi

2016-11-01

There is considerable evidence that plasma structure in nighttime equatorial F layer develops from large-scale wave structure (LSWS) in bottomside F layer. However, crucial details of how this process proceeds, from LSWS to equatorial plasma bubbles (EPBs), remain to be sorted out. A major obstacle to success is the paucity of measurements that provide a space-time description of the bottomside F layer over a broad geographical region. The transequatorial propagation (TEP) experiment is one of few methods that can do so. New findings using a TEP experiment, between Shepparton (SHP), Australia, and Oarai (ORI), Japan, are presented in two companion papers. In Paper 1 (P1), (1) off-great-circle (OGC) paths are described in terms of discrete and diffuse types, (2) descriptions of OGC paths are generalized from a single-reflection to a multiple-reflection process, and (3) discrete type is shown to be associated with an unstructured but distorted upwelling, whereas the diffuse type is shown to be associated with EPBs. In Paper 2 (P2), attention is placed on differences in east-west (EW) asymmetry, found between OGC paths from the SHP-ORI experiment and those from another near-identical TEP experiment. Differences are reconciled by allowing three distinct sources for the EW asymmetries: (1) reflection properties within an upwelling (see P1), (2) OGC paths that depend on magnetic declination of geomagnetic field (B), and (3) OGC paths supported by non-B-aligned reflectors at latitudes where inclination of B is finite.

Integrity of Helix 2-Helix 3 Domain of the PrP Protein Is Not Mandatory for Prion Replication*

PubMed Central

Salamat, Khalid; Moudjou, Mohammed; Chapuis, Jérôme; Herzog, Laetitia; Jaumain, Emilie; Béringue, Vincent; Rezaei, Human; Pastore, Annalisa; Laude, Hubert; Dron, Michel

2012-01-01

The process of prion conversion is not yet well understood at the molecular level. The regions critical for the conformational change of PrP remain mostly debated and the extent of sequence change acceptable for prion conversion is poorly documented. To achieve progress on these issues, we applied a reverse genetic approach using the Rov cell system. This allowed us to test the susceptibility of a number of insertion mutants to conversion into prion in the absence of wild-type PrP molecules. We were able to propagate several prions with 8 to 16 extra amino acids, including a polyglycine stretch and His or FLAG tags, inserted in the middle of the protease-resistant fragment. These results demonstrate the possibility to increase the length of the loop between helices H2 and H3 up to 4-fold, without preventing prion replication. They also indicate that this loop probably remains unstructured in PrPSc. We also showed that bona fide prions can be produced following insertion of octapeptides in the two C-terminal turns of H2. These insertions do not interfere with the overall fold of the H2-H3 domain indicating that the highly conserved sequence of the terminal part of H2 is not critical for the conversion. Altogether these data showed that the amplitude of modifications acceptable for prion conversion in the core of the globular domain of PrP is much greater than one might have assumed. These observations should help to refine structural models of PrPSc and elucidate the conformational changes underlying prions generation. PMID:22511770

Phylogeny and evolutionary histories of Pyrus L. revealed by phylogenetic trees and networks based on data from multiple DNA sequences.

PubMed

Zheng, Xiaoyan; Cai, Danying; Potter, Daniel; Postman, Joseph; Liu, Jing; Teng, Yuanwen

2014-11-01

Reconstructing the phylogeny of Pyrus has been difficult due to the wide distribution of the genus and lack of informative data. In this study, we collected 110 accessions representing 25 Pyrus species and constructed both phylogenetic trees and phylogenetic networks based on multiple DNA sequence datasets. Phylogenetic trees based on both cpDNA and nuclear LFY2int2-N (LN) data resulted in poor resolution, especially, only five primary species were monophyletic in the LN tree. A phylogenetic network of LN suggested that reticulation caused by hybridization is one of the major evolutionary processes for Pyrus species. Polytomies of the gene trees and star-like structure of cpDNA networks suggested rapid radiation is another major evolutionary process, especially for the occidental species. Pyrus calleryana and P. regelii were the earliest diverged Pyrus species. Two North African species, P. cordata, P. spinosa and P. betulaefolia were descendent of primitive stock Pyrus species and still share some common molecular characters. Southwestern China, where a large number of P. pashia populations are found, is probably the most important diversification center of Pyrus. More accessions and nuclear genes are needed for further understanding the evolutionary histories of Pyrus. Copyright © 2014 Elsevier Inc. All rights reserved.

Opinion evolution in different social acquaintance networks.

PubMed

Chen, Xi; Zhang, Xiao; Wu, Zhan; Wang, Hongwei; Wang, Guohua; Li, Wei

2017-11-01

Social acquaintance networks influenced by social culture and social policy have a great impact on public opinion evolution in daily life. Based on the differences between socio-culture and social policy, three different social acquaintance networks (kinship-priority acquaintance network, independence-priority acquaintance network, and hybrid acquaintance network) incorporating heredity proportion p h and variation proportion p v are proposed in this paper. Numerical experiments are conducted to investigate network topology and different phenomena during opinion evolution, using the Deffuant model. We found that in kinship-priority acquaintance networks, similar to the Chinese traditional acquaintance networks, opinions always achieve fragmentation, resulting in the formation of multiple large clusters and many small clusters due to the fact that individuals believe more in their relatives and live in a relatively closed environment. In independence-priority acquaintance networks, similar to Western acquaintance networks, the results are similar to those in the kinship-priority acquaintance network. In hybrid acquaintance networks, similar to the Chinese modern acquaintance networks, only a few clusters are formed indicating that in modern China, opinions are more likely to reach consensus on a large scale. These results are similar to the opinion evolution phenomena in modern society, proving the rationality and applicability of network models combined with social culture and policy. We also found a threshold curve p v +2p h =2.05 in the results for the final opinion clusters and evolution time. Above the threshold curve, opinions could easily reach consensus. Based on the above experimental results, a culture-policy-driven mechanism for the opinion dynamic is worth promoting in this paper, that is, opinion dynamics can be driven by different social cultures and policies through the influence of heredity and variation in interpersonal relationship networks. This finding is of great significance for predicting opinion evolution under different acquaintance networks and formulating reasonable policies based on cultural characteristics to guide public opinion.

Patterns in CH4 and CO2 concentrations across boreal rivers: Major drivers and implications for fluvial greenhouse emissions under climate change scenarios.

PubMed

Campeau, Audrey; Del Giorgio, Paul A

2014-04-01

It is now widely accepted that boreal rivers and streams are regionally significant sources of carbon dioxide (CO2), yet their role as methane (CH4) emitters, as well as the sensitivity of these greenhouse gas (GHG) emissions to climate change, are still largely undefined. In this study, we explore the large-scale patterns of fluvial CO2 and CH4 partial pressure (pCO2 , pCH4) and gas exchange (k) relative to a set of key, climate-sensitive river variables across 46 streams and rivers in two distinct boreal landscapes of Northern Québec. We use the resulting models to determine the direction and magnitude of C-gas emissions from these boreal fluvial networks under scenarios of climate change. River pCO2 and pCH4 were positively correlated, although the latter was two orders of magnitude more variable. We provide evidence that in-stream metabolism strongly influences the dynamics of surface water pCO2 and pCH4 , but whereas pCO2 is not influenced by temperature in the surveyed streams and rivers, pCH4 appears to be strongly temperature-dependent. The major predictors of ambient gas concentrations and exchange were water temperature, velocity, and DOC, and the resulting models indicate that total GHG emissions (C-CO2 equivalent) from the entire network may increase between by 13 to 68% under plausible scenarios of climate change over the next 50 years. These predicted increases in fluvial GHG emissions are mostly driven by a steep increase in the contribution of CH4 (from 36 to over 50% of total CO2 -equivalents). The current role of boreal fluvial networks as major landscape sources of C is thus likely to expand, mainly driven by large increases in fluvial CH4 emissions. © 2013 John Wiley & Sons Ltd.

Loss of integrity and atrophy in cingulate structural covariance networks in Parkinson's disease.

PubMed

de Schipper, Laura J; van der Grond, Jeroen; Marinus, Johan; Henselmans, Johanna M L; van Hilten, Jacobus J

2017-01-01

In Parkinson's disease (PD), the relation between cortical brain atrophy on MRI and clinical progression is not straightforward. Determination of changes in structural covariance networks - patterns of covariance in grey matter density - has shown to be a valuable technique to detect subtle grey matter variations. We evaluated how structural network integrity in PD is related to clinical data. 3 Tesla MRI was performed in 159 PD patients. We used nine standardized structural covariance networks identified in 370 healthy subjects as a template in the analysis of the PD data. Clinical assessment comprised motor features (Movement Disorder Society-Unified Parkinson's Disease Rating Scale; MDS-UPDRS motor scale) and predominantly non-dopaminergic features (SEverity of Non-dopaminergic Symptoms in Parkinson's Disease; SENS-PD scale: postural instability and gait difficulty, psychotic symptoms, excessive daytime sleepiness, autonomic dysfunction, cognitive impairment and depressive symptoms). Voxel-based analyses were performed within networks significantly associated with PD. The anterior and posterior cingulate network showed decreased integrity, associated with the SENS-PD score, p = 0.001 (β = - 0.265, η p 2  = 0.070) and p = 0.001 (β = - 0.264, η p 2  = 0.074), respectively. Of the components of the SENS-PD score, cognitive impairment and excessive daytime sleepiness were associated with atrophy within both networks. We identified loss of integrity and atrophy in the anterior and posterior cingulate networks in PD patients. Abnormalities of both networks were associated with predominantly non-dopaminergic features, specifically cognition and excessive daytime sleepiness. Our findings suggest that (components of) the cingulate networks display a specific vulnerability to the pathobiology of PD and may operate as interfaces between networks involved in cognition and alertness.

Uncovering the role of the flexible C-terminal tail: A model study with Strep-tagged GFP.

PubMed

Lassalle, Michael W; Kondou, Shinobu

2016-06-01

Recently, it has been recognized that, much like an electric current in an electric circuit, dynamic disruptions from flexible, unstructured regions distal to the active region are transferred through the contact network to the active site and influence protein stability and/or function. As transmembrane proteins frequently possess the β-barrel structure, studies of proteins with this topology are required. The unstructured lid segments of the β-barrel GFP protein are conserved and could play a role in the backbone stabilization required for chromophore function. A study of the disordered C-terminus and the function within the lid is necessary. In this study, we entirely truncated the flexible C-terminal tail and investigated the N-terminal Strep-tagged GFP by fluorescence spectroscopy, and the temperature- and GdnHCl-induced unfolding by circular dichroism. The introduction of the unstructured Strep-tag itself changed the unfolding pathway. Truncating the entire flexible tail did not decrease the fluorescence intensity to a large extent; however, the protein stability changed dramatically. The temperature for half-denaturation T 1/2 changed significantly from 79 °C for the wild-type to 72.8 °C for the mutant. Unfolding kinetics at different temperatures have been induced by 4 M GdnHCl, and the apparent Arrhenius activation energy decreased by 40% as compared to the wild-type.

Biased random walks on Kleinberg's spatial networks

NASA Astrophysics Data System (ADS)

Pan, Gui-Jun; Niu, Rui-Wu

2016-12-01

We investigate the problem of the particle or message that travels as a biased random walk toward a target node in Kleinberg's spatial network which is built from a d-dimensional (d = 2) regular lattice improved by adding long-range shortcuts with probability P(rij) ∼rij-α, where rij is the lattice distance between sites i and j, and α is a variable exponent. Bias is represented as a probability p of the packet to travel at every hop toward the node which has the smallest Manhattan distance to the target node. We study the mean first passage time (MFPT) for different exponent α and the scaling of the MFPT with the size of the network L. We find that there exists a threshold probability pth ≈ 0.5, for p ≥pth the optimal transportation condition is obtained with an optimal transport exponent αop = d, while for 0 < p pth, and increases with L less than a power law and get close to logarithmical law for 0 < p

Studies of structure of calcium-iron phosphate glasses by infrared, Raman and UV-Vis spectroscopies

NASA Astrophysics Data System (ADS)

Li, H. J.; Liang, X. F.; Yu, H. J.; Yang, D. Q.; Yang, S. Y.

2016-06-01

Glasses in the ternary CaO-Fe2O3-P2O5 system were prepared and studied by means of density, differential scanning calorimetry, infrared, Raman and UV-Vis spectroscopies. The results showed that density and molar volume in the glass system decreased with increasing substitution of CaO for Fe2O3. The variation of glass transition temperature and thermal stability was strictly related to the nature of bonding in the vitreous network. Spectroscopic analysis showed that substitution of CaO for Fe2O3 induced an evolution of structural units from pyrophosphate to metaphosphate species indicating the polymerization of phosphate chains and the decrease of non-bridging oxygen concentrations. With increasing substitution of CaO for Fe2O3 The P-O-Ca linkage and (P-O- Ca2+ -O-P) chains participated in the glass network by replacing P-O-Fe bonds. The absorption band of the P-O-Ca stretching mode in the glasses with high CaO content (≥32 mol%) was assigned at around 1084 cm-1. The absorption edge would fall in the region between 332 and 420 nm which are the absorption bands of Fe3+ ions.

A p-i-n junction diode based on locally doped carbon nanotube network

PubMed Central

Liu, Xiaodong; Chen, Changxin; Wei, Liangming; Hu, Nantao; Song, Chuanjuan; Liao, Chenghao; He, Rong; Dong, Xusheng; Wang, Ying; Liu, Qinran; Zhang, Yafei

2016-01-01

A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field in the SWNTs. The results showed that the forward current and the rectification ratio of the diode increased as the doping degree increased. The forward current of the device could also be increased by decreasing the channel length. A high-performance p-i-n junction diode with a high rectification ratio (~104), large forward current (~12.2 μA) and low reverse saturated current (~1.8 nA) was achieved with the OA and PEI doping time of 5 h and 18 h for a channel length of ~6 μm. PMID:26996610

A p-i-n junction diode based on locally doped carbon nanotube network.

PubMed

Liu, Xiaodong; Chen, Changxin; Wei, Liangming; Hu, Nantao; Song, Chuanjuan; Liao, Chenghao; He, Rong; Dong, Xusheng; Wang, Ying; Liu, Qinran; Zhang, Yafei

2016-03-21

A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field in the SWNTs. The results showed that the forward current and the rectification ratio of the diode increased as the doping degree increased. The forward current of the device could also be increased by decreasing the channel length. A high-performance p-i-n junction diode with a high rectification ratio (~10(4)), large forward current (~12.2 μA) and low reverse saturated current (~1.8 nA) was achieved with the OA and PEI doping time of 5 h and 18 h for a channel length of ~6 μm.

A p-i-n junction diode based on locally doped carbon nanotube network

NASA Astrophysics Data System (ADS)

Liu, Xiaodong; Chen, Changxin; Wei, Liangming; Hu, Nantao; Song, Chuanjuan; Liao, Chenghao; He, Rong; Dong, Xusheng; Wang, Ying; Liu, Qinran; Zhang, Yafei

2016-03-01

A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field in the SWNTs. The results showed that the forward current and the rectification ratio of the diode increased as the doping degree increased. The forward current of the device could also be increased by decreasing the channel length. A high-performance p-i-n junction diode with a high rectification ratio (~104), large forward current (~12.2 μA) and low reverse saturated current (~1.8 nA) was achieved with the OA and PEI doping time of 5 h and 18 h for a channel length of ~6 μm.

An informatics project and online "Knowledge Centre" supporting modern genotype-to-phenotype research.

PubMed

Webb, Adam J; Thorisson, Gudmundur A; Brookes, Anthony J

2011-05-01

Explosive growth in the generation of genotype-to-phenotype (G2P) data necessitates a concerted effort to tackle the logistical and informatics challenges this presents. The GEN2PHEN Project represents one such effort, with a broad strategy of uniting disparate G2P resources into a hybrid centralized-federated network. This is achieved through a holistic strategy focussed on three overlapping areas: data input standards and pipelines through which to submit and collect data (data in); federated, independent, extendable, yet interoperable database platforms on which to store and curate widely diverse datasets (data storage); and data formats and mechanisms with which to exchange, combine, and extract data (data exchange and output). To fully leverage this data network, we have constructed the "G2P Knowledge Centre" (http://www.gen2phen.org). This central platform provides holistic searching of the G2P data domain allied with facilities for data annotation and user feedback, access to extensive G2P and informatics resources, and tools for constructing online working communities centered on the G2P domain. Through the efforts of GEN2PHEN, and through combining data with broader community-derived knowledge, the Knowledge Centre opens up exciting possibilities for organizing, integrating, sharing, and interpreting new waves of G2P data in a collaborative fashion. © 2011 Wiley-Liss, Inc.

Hypoxia induces a phase transition within a kinase signaling network in cancer cells.

PubMed

Wei, Wei; Shi, Qihui; Remacle, Francoise; Qin, Lidong; Shackelford, David B; Shin, Young Shik; Mischel, Paul S; Levine, R D; Heath, James R

2013-04-09

Hypoxia is a near-universal feature of cancer, promoting glycolysis, cellular proliferation, and angiogenesis. The molecular mechanisms of hypoxic signaling have been intensively studied, but the impact of changes in oxygen partial pressure (pO2) on the state of signaling networks is less clear. In a glioblastoma multiforme (GBM) cancer cell model, we examined the response of signaling networks to targeted pathway inhibition between 21% and 1% pO2. We used a microchip technology that facilitates quantification of a panel of functional proteins from statistical numbers of single cells. We find that near 1.5% pO2, the signaling network associated with mammalian target of rapamycin (mTOR) complex 1 (mTORC1)--a critical component of hypoxic signaling and a compelling cancer drug target--is deregulated in a manner such that it will be unresponsive to mTOR kinase inhibitors near 1.5% pO2, but will respond at higher or lower pO2 values. These predictions were validated through experiments on bulk GBM cell line cultures and on neurosphere cultures of a human-origin GBM xenograft tumor. We attempt to understand this behavior through the use of a quantitative version of Le Chatelier's principle, as well as through a steady-state kinetic model of protein interactions, both of which indicate that hypoxia can influence mTORC1 signaling as a switch. The Le Chatelier approach also indicates that this switch may be thought of as a type of phase transition. Our analysis indicates that certain biologically complex cell behaviors may be understood using fundamental, thermodynamics-motivated principles.

Effects of a Social Network HIV/STD Prevention Intervention for Men Who Have Sex with Men in Russia and Hungary: A Randomized Controlled Trial

PubMed Central

Amirkhanian, Yuri A.; Kelly, Jeffrey A.; Takacs, Judit; McAuliffe, Timothy L.; Kuznetsova, Anna V.; Toth, Tamas P.; Mocsonaki, Laszlo; DiFranceisco, Wayne J.; Meylakhs, Anastasia

2015-01-01

Objective To test a novel social network HIV risk reduction intervention for MSM in Russia and Hungary, where same-sex behavior is stigmatized and men may best be reached through their social network connections. Design A 2-arm trial with 18 sociocentric networks of MSM randomized to the social network intervention or standard HIV/STD testing/counseling. Setting St. Petersburg, Russia and Budapest, Hungary. Participants 18 “seeds” from community venues invited the participation of their MSM friends who, in turn, invited their own MSM friends into the study, a process that continued outward until eighteen 3-ring sociocentric networks (mean size=35 members, n=626) were recruited. Intervention Empirically-identified network leaders were trained and guided to convey HIV prevention advice to other network members. Main Outcome and Measures Changes in sexual behavior from baseline to 3- and 12-month followup, with composite HIV/STD incidence measured at 12-months to corroborate behavior changes. Results There were significant reductions between baseline, first followup, and second followup in the intervention versus comparison arm for proportion of men engaging in any unprotected anal intercourse (P=.04); UAI with a nonmain partner (P=.04); and UAI with multiple partners (P=.002). The mean percentage of unprotected AI acts significantly declined (P=.001), as well as the mean number of UAI acts among men who initially had multiple partners (P=.05). Biological HIV/STD incidence was 15% in comparison condition networks and 9% in intervention condition networks. Conclusions Even where same-sex behavior is stigmatized, it is possible to reach MSM and deliver HIV prevention through their social networks. PMID:25565495

Oxidation of p53 through DNA Charge Transport Involves a Network of Disulfides within the DNA-Binding Domain

PubMed Central

2016-01-01

Transcription factor p53 plays a critical role in the cellular response to stress stimuli. We have seen that p53 dissociates selectively from various promoter sites as a result of oxidation at long-range through DNA-mediated charge transport (CT). Here, we examine this chemical oxidation and determine the residues in p53 that are essential for oxidative dissociation, focusing on the network of cysteine residues adjacent to the DNA-binding site. Of the eight mutants studied, only the C275S mutation shows decreased affinity for the Gadd45 promoter site. However, both mutations C275S and C277S result in substantial attenuation of oxidative dissociation, with C275S causing the most severe attenuation. Differential thiol labeling was used to determine the oxidation states of cysteine residues within p53 after DNA-mediated oxidation. Reduced cysteines were iodoacetamide-labeled, whereas oxidized cysteines participating in disulfide bonds were 13C2D2-iodoacetamide-labeled. Intensities of respective iodoacetamide-modified peptide fragments were analyzed by mass spectrometry. A distinct shift in peptide labeling toward 13C2D2-iodoacetamide-labeled cysteines is observed in oxidized samples, confirming that chemical oxidation of p53 occurs at long range. All observable cysteine residues trend toward the heavy label under conditions of DNA CT, indicating the formation of multiple disulfide bonds among the cysteine network. On the basis of these data, it is proposed that disulfide formation involving C275 is critical for inducing oxidative dissociation of p53 from DNA. PMID:25584637

Social networks, social support, and burden in relationships, and mortality after breast cancer diagnosis in the Life After Breast Cancer Epidemiology (LACE) study.

PubMed

Kroenke, Candyce H; Quesenberry, Charles; Kwan, Marilyn L; Sweeney, Carol; Castillo, Adrienne; Caan, Bette J

2013-01-01

Larger social networks have been associated with lower breast cancer mortality. The authors evaluated how levels of social support and burden influenced this association. We included 2,264 women from the Life After Cancer Epidemiology study who were diagnosed with early-stage, invasive breast cancer between 1997 and 2000, and provided data on social networks (spouse or intimate partner, religious/social ties, volunteering, time socializing with friends, and number of first-degree female relatives), social support, and caregiving. 401 died during a median follow-up of 10.8 years follow-up with 215 from breast cancer. We used delayed entry Cox proportional hazards regression to evaluate associations. In multivariate-adjusted analyses, social isolation was unrelated to recurrence or breast cancer-specific mortality. However, socially isolated women had higher all-cause mortality (HR = 1.34, 95 % CI: 1.03-1.73) and mortality from other causes (HR = 1.79, 95 % CI: 1.19-2.68). Levels of social support and burden modified associations. Among those with low, but not high, levels of social support from friends and family, lack of religious/social participation (HR = 1.58, 95 % CI: 1.07-2.36, p = 0.02, p interaction = 0.01) and lack of volunteering (HR = 1.78, 95 % CI: 1.15-2.77, p = 0.01, p interaction = 0.01) predicted higher all-cause mortality. In cross-classification analyses, only women with both small networks and low levels of support (HR = 1.61, 95 % CI: 1.10-2.38) had a significantly higher risk of mortality than women with large networks and high levels of support; women with small networks and high levels of support had no higher risk of mortality (HR = 1.13, 95 % CI: 0.74-1.72). Social networks were also more important for caregivers versus noncaregivers. Larger social networks predicted better prognosis after breast cancer, but associations depended on the quality and burden of family relationships.

Neural Network Prediction of ICU Length of Stay Following Cardiac Surgery Based on Pre-Incision Variables

PubMed Central

Pothula, Venu M.; Yuan, Stanley C.; Maerz, David A.; Montes, Lucresia; Oleszkiewicz, Stephen M.; Yusupov, Albert; Perline, Richard

2015-01-01

Background Advanced predictive analytical techniques are being increasingly applied to clinical risk assessment. This study compared a neural network model to several other models in predicting the length of stay (LOS) in the cardiac surgical intensive care unit (ICU) based on pre-incision patient characteristics. Methods Thirty six variables collected from 185 cardiac surgical patients were analyzed for contribution to ICU LOS. The Automatic Linear Modeling (ALM) module of IBM-SPSS software identified 8 factors with statistically significant associations with ICU LOS; these factors were also analyzed with the Artificial Neural Network (ANN) module of the same software. The weighted contributions of each factor (“trained” data) were then applied to data for a “new” patient to predict ICU LOS for that individual. Results Factors identified in the ALM model were: use of an intra-aortic balloon pump; O2 delivery index; age; use of positive cardiac inotropic agents; hematocrit; serum creatinine ≥ 1.3 mg/deciliter; gender; arterial pCO2. The r2 value for ALM prediction of ICU LOS in the initial (training) model was 0.356, p <0.0001. Cross validation in prediction of a “new” patient yielded r2 = 0.200, p <0.0001. The same 8 factors analyzed with ANN yielded a training prediction r2 of 0.535 (p <0.0001) and a cross validation prediction r2 of 0.410, p <0.0001. Two additional predictive algorithms were studied, but they had lower prediction accuracies. Our validated neural network model identified the upper quartile of ICU LOS with an odds ratio of 9.8(p <0.0001). Conclusions ANN demonstrated a 2-fold greater accuracy than ALM in prediction of observed ICU LOS. This greater accuracy would be presumed to result from the capacity of ANN to capture nonlinear effects and higher order interactions. Predictive modeling may be of value in early anticipation of risks of post-operative morbidity and utilization of ICU facilities. PMID:26710254

A Repeated Measures Experiment of School Playing Environment to Increase Physical Activity and Enhance Self-Esteem in UK School Children

PubMed Central

Wood, Carly; Gladwell, Valerie; Barton, Jo

2014-01-01

School playtime provides daily opportunities for children to be active outdoors, but only makes small contributions to physical activity (PA) requirements. Natural environments facilitate unstructured PA and children report a preference for play in nature. Thus, play on the school field might encourage children to be more active during playtime. The primary aim of this study was to examine the impact of the school playing environment on children's PA. Descriptive data and fitness were assessed in 25 children aged 8–9 years from a single primary school. Over two consecutive weeks participants were allocated to either play on the school field or playground during playtime. The order of play in the two areas was randomised and counterbalanced. Moderate to vigorous PA (MVPA) was assessed during playtime on the last two days of each week using accelerometers. There was a significant interaction of environment and sex on MVPA during morning play (F(1,22) = 6.27; P<0.05; np 2 = 0.222), but not during lunch (P>0.05; np 2 = 0.060) or all of playtime combined (P>0.05; np 2 = 0.140). During morning play boys were significantly more active than girls on the playground (t(23) = 1.32; P<0.01; n2 = 0.291), but not on the field (P>0.05; n2 = 0.071). For lunch (F(1,22) = 24,11; P<0.001; np 2 = 0.523) and all of playtime combined (F(1,22) = 33.67; P<0.001; np 2 = 0.616) there was a significant effect of environment. There was also a significant main effect of sex during lunch (F(1,22) = 11.56; P<0.01; np 2 = 0.344) and all of playtime combined (F(1,22) = 12.37; P<0.01; np 2 = 0.371). MVPA was higher on the field and boys were more active than girls. Play on the field leads to increases in MVPA, particularly in girls. The promising trend for the effect of the natural environment on MVPA indicates that interventions aimed at increasing MVPA should use the natural environment and that schools should encourage greater use of their natural areas to increase PA. PMID:25264610

A repeated measures experiment of school playing environment to increase physical activity and enhance self-esteem in UK school children.

PubMed

Wood, Carly; Gladwell, Valerie; Barton, Jo

2014-01-01

School playtime provides daily opportunities for children to be active outdoors, but only makes small contributions to physical activity (PA) requirements. Natural environments facilitate unstructured PA and children report a preference for play in nature. Thus, play on the school field might encourage children to be more active during playtime. The primary aim of this study was to examine the impact of the school playing environment on children's PA. Descriptive data and fitness were assessed in 25 children aged 8-9 years from a single primary school. Over two consecutive weeks participants were allocated to either play on the school field or playground during playtime. The order of play in the two areas was randomised and counterbalanced. Moderate to vigorous PA (MVPA) was assessed during playtime on the last two days of each week using accelerometers. There was a significant interaction of environment and sex on MVPA during morning play (F(1,22) = 6.27; P<0.05; np2 = 0.222), but not during lunch (P>0.05; np2 = 0.060) or all of playtime combined (P>0.05; np2 = 0.140). During morning play boys were significantly more active than girls on the playground (t(23) = 1.32; P<0.01; n2 = 0.291), but not on the field (P>0.05; n2 = 0.071). For lunch (F(1,22) = 24,11; P<0.001; np2 = 0.523) and all of playtime combined (F(1,22) = 33.67; P<0.001; np2 = 0.616) there was a significant effect of environment. There was also a significant main effect of sex during lunch (F(1,22) = 11.56; P<0.01; np2 = 0.344) and all of playtime combined (F(1,22) = 12.37; P<0.01; np2 = 0.371). MVPA was higher on the field and boys were more active than girls. Play on the field leads to increases in MVPA, particularly in girls. The promising trend for the effect of the natural environment on MVPA indicates that interventions aimed at increasing MVPA should use the natural environment and that schools should encourage greater use of their natural areas to increase PA.

Common arbuscular mycorrhizal networks amplify competition for phosphorus between seedlings and established plants.

PubMed

Merrild, Marie P; Ambus, Per; Rosendahl, Søren; Jakobsen, Iver

2013-10-01

Common mycorrhizal networks (CMNs) influence competition between plants, but reports regarding their precise effect are conflicting. We studied CMN effects on phosphorus (P) uptake and growth of seedlings as influenced by various disruptions of network components. Tomato (Solanum lycopersicon) seedlings grew into established networks of Rhizophagus irregularis and cucumber (Cucumis sativus) in two experiments. One experiment studied seedling uptake of (32)P in the network in response to cutting of cucumber shoots; the other analysed seedling uptake of P and nitrogen (N) in the presence of intact or severed arbuscular mycorrhizal fungus networks and at two soil P concentrations. Pre-established and intact networks suppressed growth of tomato seedlings. Cutting of cucumber shoots mitigated P deficiency symptoms of seedlings, which obtained access to P in the extraradical mycelium and thereby showed improved growth. Solitary seedlings growing in a network patch that had been severed from the CMN also grew much better than seedlings of the corresponding CMN. Interspecific and size-asymmetric competition between plants may be amplified rather than relaxed by CMNs that transfer P to large plants providing most carbon and render small plants P deficient. It is likely that grazing or senescence of the large plants will alleviate the network-induced suppression of seedling growth. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Revisiting Social Network Utilization by Physicians-in-Training.

PubMed

Black, Erik W; Thompson, Lindsay A; Duff, W Patrick; Dawson, Kara; Saliba, Heidi; Black, Nicole M Paradise

2010-06-01

To measure and compare the frequency and content of online social networking among 2 cohorts of medical students and residents (2007 and 2009). Using the online social networking application Facebook, we evaluated social networking profiles for 2 cohorts of medical students (n  =  528) and residents (n  =  712) at the University of Florida in Gainesville. Objective measures included existence of a profile, whether it was made private, and whether any personally identifiable information was included. Subjective outcomes included photographic content, affiliated social groups, and personal information not generally disclosed in a doctor-patient encounter. We compared our results to our previously published and reported data from 2007. Social networking continues to be common amongst physicians-in-training, with 39.8% of residents and 69.5% of medical students maintaining Facebook accounts. Residents' participation significantly increased (P < .01) when compared to the 2007 data. Individuals in the 2009 cohort had significantly more "friends" (P < .01), belonged to more "groups" (P < .01), and were more likely to limit public access to their profiles through the use of privacy settings (P < .01) than the individuals in the 2007 cohort. Online social networking application use by physicians-in-training remains common. While most now limit access to their profiles, personal profiles that still allow public access exhibited a few instances of unprofessional behavior. Concerns remain related to the discovery of content in violation of patient privacy and the expansive and impersonal networks of online "friends" who may view profiles.

Ag-bridged Ag2O nanowire network/TiO2 nanotube array p-n heterojunction as a highly efficient and stable visible light photocatalyst.

PubMed

Liu, Chengbin; Cao, Chenghao; Luo, Xubiao; Luo, Shenglian

2015-03-21

A unique Ag-bridged Ag2O nanowire network/TiO2 nanotube array p-n heterojunction (Ag-Ag2O/TiO2 NT) was fabricated by simple electrochemical method. Ag nanoparticles were firstly electrochemically deposited onto the surface of TiO2 NT and then were partly oxidized to Ag2O nanowires while the rest of Ag mother nanoparticles were located at the junctions of Ag2O nanowire network. The Ag-Ag2O/TiO2 NT heterostructure exhibited strong visible-light response, effective separation of photogenerated carriers, and high adsorption capacity. The integration of Ag-Ag2O self-stability structure and p-n heterojunction permitted high and stable photocatalytic activity of Ag-Ag2O/TiO2 NT heterostructure photocatalyst. Under 140-min visible light irradiation, the photocatalytic removal efficiency of both dye acid orange 7 (AO7) and industrial chemical p-nitrophenol (PNP) over Ag-Ag2O/TiO2 NT reached nearly 100% much higher than 17% for AO7 or 13% for PNP over bare TiO2 NT. After 5 successive cycles under 600-min simulated solar light irradiation, Ag-Ag2O/TiO2 NT remained highly stable photocatalytic activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Improvement in American Board of Surgery in-training examination performance with a multidisciplinary surgeon-directed integrated learning platform.

PubMed

Dua, Anahita; Sudan, Ranjan; Desai, Sapan S

2014-01-01

The American Board of Surgery In-Training Examination (ABSITE) is a predictor of resident performance on the general surgery-qualifying examination and plays a role in obtaining competitive fellowships. A learning management system (LMS) permits the delivery of a structured curriculum that appeals to the modern resident owing to the ease of accessibility and all-in-one organization. This study hypothesizes that trainees using a structured surgeon-directed LMS will achieve improved ABSITE scores compared with those using an unstructured approach to the examination. A multidisciplinary print and digital review course with practice questions, review textbooks, weekly reading assignments, and slide and audio reviews integrated within an online LMS was made available to postgraduate year (PGY)-3 and PGY-4 residents in 2008 and 2009. Surveys were emailed requesting ABSITE scores to compare outcomes in those trainees that used the course with those who used an unstructured approach. Statistical analysis was conducted via descriptive statistics and Pearson chi-square with p < 0.05 deemed statistically significant. Surveys were mailed to 508 trainees. There was an 80% (408) response rate. Residents who used structured approaches in both the years achieved the highest scores, followed by those who adopted a structured approach in PGY-4. The residents using an unstructured approach in both the years showed no significant improvement. Residents who used a structured LMS performed significantly better than their counterparts who used an unstructured approach. A properly constructed online education curriculum has the potential to improve ABSITE scores. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Secure and Privacy-Preserving Distributed Information Brokering

ERIC Educational Resources Information Center

Li, Fengjun

2010-01-01

As enormous structured, semi-structured and unstructured data are collected and archived by organizations in many realms ranging from business to health networks to government agencies, the needs for efficient yet secure inter-organization information sharing naturally arise. Unlike early information sharing approaches that only involve a small…

Competing contact processes in the Watts-Strogatz network

NASA Astrophysics Data System (ADS)

Rybak, Marcin; Malarz, Krzysztof; Kułakowski, Krzysztof

2016-06-01

We investigate two competing contact processes on a set of Watts-Strogatz networks with the clustering coefficient tuned by rewiring. The base for network construction is one-dimensional chain of N sites, where each site i is directly linked to nodes labelled as i ± 1 and i ± 2. So initially, each node has the same degree k i = 4. The periodic boundary conditions are assumed as well. For each node i the links to sites i + 1 and i + 2 are rewired to two randomly selected nodes so far not-connected to node i. An increase of the rewiring probability q influences the nodes degree distribution and the network clusterization coefficient 𝓒. For given values of rewiring probability q the set 𝓝(q)={𝓝1,𝓝2,...,𝓝 M } of M networks is generated. The network's nodes are decorated with spin-like variables s i ∈ { S,D }. During simulation each S node having a D-site in its neighbourhood converts this neighbour from D to S state. Conversely, a node in D state having at least one neighbour also in state D-state converts all nearest-neighbours of this pair into D-state. The latter is realized with probability p. We plot the dependence of the nodes S final density n S T on initial nodes S fraction n S 0. Then, we construct the surface of the unstable fixed points in (𝓒, p, n S 0) space. The system evolves more often toward n S T for (𝓒, p, n S 0) points situated above this surface while starting simulation with (𝓒, p, n S 0) parameters situated below this surface leads system to n S T =0. The points on this surface correspond to such value of initial fraction n S * of S nodes (for fixed values 𝓒 and p) for which their final density is n S T=1/2.

Wavelet multiresolution complex network for decoding brain fatigued behavior from P300 signals

NASA Astrophysics Data System (ADS)

Gao, Zhong-Ke; Wang, Zi-Bo; Yang, Yu-Xuan; Li, Shan; Dang, Wei-Dong; Mao, Xiao-Qian

2018-09-01

Brain-computer interface (BCI) enables users to interact with the environment without relying on neural pathways and muscles. P300 based BCI systems have been extensively used to achieve human-machine interaction. However, the appearance of fatigue symptoms during operation process leads to the decline in classification accuracy of P300. Characterizing brain cognitive process underlying normal and fatigue conditions constitutes a problem of vital importance in the field of brain science. We in this paper propose a novel wavelet decomposition based complex network method to efficiently analyze the P300 signals recorded in the image stimulus test based on classical 'Oddball' paradigm. Initially, multichannel EEG signals are decomposed into wavelet coefficient series. Then we construct complex network by treating electrodes as nodes and determining the connections according to the 2-norm distances between wavelet coefficient series. The analysis of topological structure and statistical index indicates that the properties of brain network demonstrate significant distinctions between normal status and fatigue status. More specifically, the brain network reconfiguration in response to the cognitive task in fatigue status is reflected as the enhancement of the small-worldness.

Charge Requirements for Proton Gradient-driven Translocation of Anthrax Toxin*

PubMed Central

Brown, Michael J.; Thoren, Katie L.; Krantz, Bryan A.

2011-01-01

Anthrax lethal toxin is used as a model system to study protein translocation. The toxin is composed of a translocase channel, called protective antigen (PA), and an enzyme, called lethal factor (LF). A proton gradient (ΔpH) can drive LF unfolding and translocation through PA channels; however, the mechanism of ΔpH-mediated force generation, substrate unfolding, and establishment of directionality are poorly understood. One recent hypothesis suggests that the ΔpH may act through changes in the protonation state of residues in the substrate. Here we report the charge requirements of LF's amino-terminal binding domain (LFN) using planar lipid bilayer electrophysiology. We found that acidic residues are required in LFN to utilize a proton gradient for translocation. Constructs lacking negative charges in the unstructured presequence of LFN translocate independently of the ΔpH driving force. Acidic residues markedly increase the rate of ΔpH-driven translocation, and the presequence is optimized in its natural acidic residue content for efficient ΔpH-driven unfolding and translocation. We discuss a ΔpH-driven charge state Brownian ratchet mechanism for translocation, where glutamic and aspartic acid residues in the substrate are the “molecular teeth” of the ratchet. Our Brownian ratchet model includes a mechanism for unfolding and a novel role for positive charges, which we propose chaperone negative charges through the PA channel during ΔpH translocation. PMID:21507946

Selective impairment of attention networks during propofol anesthesia after gynecological surgery in middle-aged women.

PubMed

Chen, Chen; Xu, Guang-hong; Li, Yuan-hai; Tang, Wei-xiang; Wang, Kai

2016-04-15

Postoperative cognitive dysfunction is a common complication of anesthesia and surgery. Attention networks are essential components of cognitive function and are subject to impairment after anesthesia and surgery. It is not known whether such impairment represents a global attention deficit or relates to a specific attention network. We used an Attention Network Task (ANT) to examine the efficiency of the alerting, orienting, and executive control attention networks in middle-aged women (40-60 years) undergoing gynecologic surgery. A matched group of medical inpatients were recruited as a control. Fifty female patients undergoing gynecologic surgery (observation group) and 50 female medical inpatients (control group) participated in this study. Preoperatively patients were administered a mini-mental state examination as a screening method. The preoperative efficiencies of three attention networks in an attention network test were compared to the 1st and 5th post-operative days. The control group did not have any significant attention network impairments. On the 1st postoperative day, significant impairment was shown in the alerting (p=0.003 vs. control group, p=0.015 vs. baseline), orienting (p<0.001 vs. both baseline level and control group), and executive control networks (p=0.007 vs. control group, p=0.002 vs. baseline) of the observation group. By the 5th postoperative day, the alerting network efficiency had recovered to preoperative levels (p=0.464 vs. baseline) and the orienting network efficiency had recovered partially (p=0.031 vs. 1st post-operative day), but not to preoperative levels (p=0.01 vs. baseline). The executive control network did not recover by the 5th postoperative day (p=0.001 vs. baseline, p=0.680 vs. 1st post-operative day). Attention networks of middle-aged women show a varying degree of significant impairment and differing levels of recovery after surgery and propofol anesthetic. Copyright © 2016 Elsevier B.V. All rights reserved.

Revealing determinants of two-phase dynamics of P53 network under gamma irradiation based on a reduced 2D relaxation oscillator model.

PubMed

Demirkıran, Gökhan; Kalaycı Demir, Güleser; Güzeliş, Cüneyt

2018-02-01

This study proposes a two-dimensional (2D) oscillator model of p53 network, which is derived via reducing the multidimensional two-phase dynamics model into a model of ataxia telangiectasia mutated (ATM) and Wip1 variables, and studies the impact of p53-regulators on cell fate decision. First, the authors identify a 6D core oscillator module, then reduce this module into a 2D oscillator model while preserving the qualitative behaviours. The introduced 2D model is shown to be an excitable relaxation oscillator. This oscillator provides a mechanism that leads diverse modes underpinning cell fate, each corresponding to a cell state. To investigate the effects of p53 inhibitors and the intrinsic time delay of Wip1 on the characteristics of oscillations, they introduce also a delay differential equation version of the 2D oscillator. They observe that the suppression of p53 inhibitors decreases the amplitudes of p53 oscillation, though the suppression increases the sustained level of p53. They identify Wip1 and P53DINP1 as possible targets for cancer therapies considering their impact on the oscillator, supported by biological findings. They model some mutations as critical changes of the phase space characteristics. Possible cancer therapeutic strategies are then proposed for preventing these mutations' effects using the phase space approach.

Improving Urban Minority Girls' Health Via Community Summer Programming.

PubMed

Bohnert, Amy M; Bates, Carolyn R; Heard, Amy M; Burdette, Kimberly A; Ward, Amanda K; Silton, Rebecca L; Dugas, Lara R

2017-12-01

Summertime has emerged as a high-risk period for weight gain among low-income minority youth who often experience a lack of resources when not attending school. Structured programming may be an effective means of reducing risk for obesity by improving obesogenic behaviors among these youth. The current multi-method study examined sedentary time, physical activity, and dietary intake among low-income urban minority girls in two contexts: an unstructured summertime setting and in the context of a structured 4-week community-based summer day camp program promoting physical activity. Data were analyzed using paired-sample t tests and repeated-measure analyses of variance with significance at the p < .05 level. Results evidenced no significant differences in total calories and fat consumed between the unstructured and structured settings. Participants exhibited significant increases in fruit consumption and physical activity and significant decreases in sedentary time of over 2 h/day and dairy consumption when engaged in structured summer programming. All improvements were independent of weight status and age, and African-American participants evidenced greater changes in physical activity during programming. The study concludes that structured, community-based summertime programming may be associated with fewer obesogenic behaviors in low-income urban youth and may be a powerful tool to address disparities in weight gain and obesity among high-risk samples.

Pace: Privacy-Protection for Access Control Enforcement in P2P Networks

NASA Astrophysics Data System (ADS)

Sánchez-Artigas, Marc; García-López, Pedro

In open environments such as peer-to-peer (P2P) systems, the decision to collaborate with multiple users — e.g., by granting access to a resource — is hard to achieve in practice due to extreme decentralization and the lack of trusted third parties. The literature contains a plethora of applications in which a scalable solution for distributed access control is crucial. This fact motivates us to propose a protocol to enforce access control, applicable to networks consisting entirely of untrusted nodes. The main feature of our protocol is that it protects both sensitive permissions and sensitive policies, and does not rely on any centralized authority. We analyze the efficiency (computational effort and communication overhead) as well as the security of our protocol.

The Association between Social Network Betweenness and Coronary Calcium: A Baseline Study of Patients with a High Risk of Cardiovascular Disease

PubMed Central

Joo, Won-tak; Lee, Chan Joo; Oh, Jaewon; Kim, In-Cheol; Lee, Sang-Hak; Kang, Seok-Min; Kim, Hyeon Chang; Park, Sungha; Youm, Yoosik

2018-01-01

Aim: The association of social networks with cardiovascular disease (CVD) has been demonstrated through various studies. This study aimed to examine the association between social network betweenness–a network position of mediating between diverse social groups–and coronary artery calcium. Methods: The data of 1,384 participants from the Cardiovascular and Metabolic Disease Etiology Research Center–High Risk Cohort, a prospective cohort study enrolling patients with a high risk of developing CVD (clinicaltrials.gov: NCT02003781), were analyzed. The deficiency in social network betweenness was measured in two ways: only-family networks, in which a respondent had networks with only family members, and no-cutpoint networks, in which the respondent does not function as a point of bridging between two or more social groups that are not directly connected. Results: Participants who had higher coronary artery calcium scores (CACSs) were likely to have a smaller network size (p < 0.001), only-family networks (p < 0.001), and no-cutpoint networks (p < 0.001). Multiple logistic regression analyses revealed no significant association between network size and CACS. Only no-cutpoint networks had a significant relationship with CACS > 400 (odds ratio, 1.72; 95% confidence interval, 1.07–2.77; p = 0.026). The association was stronger among older (age > 60 years) and female respondents. Conclusion: Deficiency in social network betweenness is closely related to coronary calcium in participants with a high risk of CVD. To generalize these results to a general population, further study should be performed. PMID:28740058

Social networks, leisure activities and maximum tongue pressure: cross-sectional associations in the Nagasaki Islands Study

PubMed Central

Nagayoshi, Mako; Higashi, Miho; Takamura, Noboru; Tamai, Mami; Koyamatsu, Jun; Yamanashi, Hirotomo; Kadota, Koichiro; Sato, Shimpei; Kawashiri, Shin-ya; Koyama, Zenya; Saito, Toshiyuki; Maeda, Takahiro

2017-01-01

Objectives Social environment is often associated with health outcomes, but epidemiological evidence for its effect on oral frailty, a potential risk factor for aspiration, is sparse. This study aimed to assess the association between social environment and tongue pressure, as an important measure of oral function. The study focused on family structure, social networks both with and beyond neighbours, and participation in leisure activities. Design A population-based cross-sectional study. Setting Annual health check-ups in a rural community in Japan. Participants A total of 1982 participants, all over 40 years old. Anyone with missing data for the main outcome (n=14) was excluded. Outcome measures Tongue pressure was measured three times, and the maximum tongue pressure was used for analysis. A multivariable adjusted regression model was used to calculate parameter estimates (B) for tongue pressure. Results Having a social network involving neighbours (B=2.43, P=0.0001) and taking part in leisure activities (B=1.58, P=0.005) were independently associated with higher tongue pressure, but there was no link with social networks beyond neighbours (B=0.23, P=0.77). Sex-specific analyses showed that for men, having a partner was associated with higher tongue pressure, independent of the number of people in the household (B=2.26, P=0.01), but there was no association among women (B=−0.24, P=0.72; P-interaction=0.059). Conclusions Having a social network involving neighbours and taking part in leisure activities were independently associated with higher tongue pressure. Marital status may be an important factor in higher tongue pressure in men. PMID:29217718

Social networks, leisure activities and maximum tongue pressure: cross-sectional associations in the Nagasaki Islands Study.

PubMed

Nagayoshi, Mako; Higashi, Miho; Takamura, Noboru; Tamai, Mami; Koyamatsu, Jun; Yamanashi, Hirotomo; Kadota, Koichiro; Sato, Shimpei; Kawashiri, Shin-Ya; Koyama, Zenya; Saito, Toshiyuki; Maeda, Takahiro

2017-12-06

Social environment is often associated with health outcomes, but epidemiological evidence for its effect on oral frailty, a potential risk factor for aspiration, is sparse. This study aimed to assess the association between social environment and tongue pressure, as an important measure of oral function. The study focused on family structure, social networks both with and beyond neighbours, and participation in leisure activities. A population-based cross-sectional study. Annual health check-ups in a rural community in Japan. A total of 1982 participants, all over 40 years old. Anyone with missing data for the main outcome (n=14) was excluded. Tongue pressure was measured three times, and the maximum tongue pressure was used for analysis. A multivariable adjusted regression model was used to calculate parameter estimates (B) for tongue pressure. Having a social network involving neighbours (B=2.43, P=0.0001) and taking part in leisure activities (B=1.58, P=0.005) were independently associated with higher tongue pressure, but there was no link with social networks beyond neighbours (B=0.23, P=0.77). Sex-specific analyses showed that for men, having a partner was associated with higher tongue pressure, independent of the number of people in the household (B=2.26, P=0.01), but there was no association among women (B=-0.24, P=0.72; P-interaction=0.059). Having a social network involving neighbours and taking part in leisure activities were independently associated with higher tongue pressure. Marital status may be an important factor in higher tongue pressure in men. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Development of an Aero-Optics Software Library and Integration into Structured Overset and Unstructured Computational Fluid Dynamics (CFD) Flow Solvers

DTIC Science & Technology

2011-04-01

some similarities to the far- field (i.e. atmospheric ) propagation, but due to the interactions between turbulence length scales, beam wavelengths...equivalently, phase differences, have been used to characterize the beam distortion caused by the unsteady turbulent flow field. A Partially-Averaged Navier...A., Wang, M., and Moin, P., “Computational Study of Aero-Optical Distortion by Turbulent Wake,” AIAA Paper 2005-4655. [11] Mani, A., Wang, M., and

Who do you know? Developing and Analyzing Entrepreneur Networks: An Analysis of the Entrepreneurial Environment of Kampala, Uganda

DTIC Science & Technology

2013-11-04

the Army Research Office. vii 1 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 May 2013 “Who do...own specific centrality metrics. 2 | P a g e Network Science Center, West Point www.netscience.usma.edu 845.938.0804 Background The...of the world’s social and economic problems. Major international organizations such as the World Bank , International Monetary Fund, and the United

Postnatal developmental changes in activation profiles of the respiratory neuronal network in the rat ventral medulla

PubMed Central

Oku, Yoshitaka; Masumiya, Haruko; Okada, Yasumasa

2007-01-01

Two putative respiratory rhythm generators (RRGs), the para-facial respiratory group (pFRG) and the pre-Bötzinger complex (preBötC), have been identified in the neonatal rodent brainstem. To elucidate their functional roles during the neonatal period, we evaluated developmental changes of these RRGs by optical imaging using a voltage-sensitive dye. Optical signals, recorded from the ventral medulla of brainstem–spinal cord preparations of neonatal (P0–P4) rats (n = 44), were analysed by a cross correlation method. With development during the first few postnatal days, the respiratory-related activity in the pFRG reduced and shifted from a preinspiratory (P0–P1) to an inspiratory (P2–P4) pattern, whereas preBötC activity remained unchanged. The μ-opioid agonist [d-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO) augmented preinspiratory activity in the pFRG, while the μ-opioid antagonist naloxone induced changes in spatiotemporal activation profiles that closely mimicked the developmental changes. These results are consistent with the recently proposed hypothesis by Janczewski and Feldman that the pFRG is activated to compensate for the depression of the preBötC by perinatal opiate surge. We conclude that significant reorganization of the respiratory neuronal network, characterized by a reduction of preinspiratory activity in the pFRG, occurs at P1–P2 in rats. The changes in spatiotemporal activation profiles of the pFRG neurones may reflect changes in the mode of coupling of the two respiratory rhythm generators. PMID:17884928

Intelligent system for automatic feature detection and selection or identification

DOEpatents

Sun, Chuen-Tsai; Jang, Jyh-Shing; Fu, Chi-Yung

1997-01-01

A neural network uses a fuzzy membership function, the parameters of which are adaptive during the training process, to parameterize the interconnection weights between an (n-1)'th layer and an n'th layer of the network. Each j'th node in each k'th layer of the network except the input layer produces its output value y.sub.k,j according to the function ##EQU1## where N.sub.k-1 is the number of nodes in layer k-1, i indexes the nodes of layer k-1 and all the w.sub.k,i,j are interconnection weights. The interconnection weights to all nodes j in the n'th layer are given by w.sub.n,i,j =w.sub.n,j (i, p.sub.n,j,1, . . . , p.sub.n,j,p.sbsb.n). The apparatus is trained by setting values for at least one of the parameters p.sub.n,j,1, . . . , p.sub.n,j,Pn. Preferably the number of parameters P.sub.n is less than the number of nodes N.sub.n-1 in layer n-1. w.sub.n,j (i,p.sub.n,j,1, . . . , p.sub.n,j,Pn) can be convex in i, and it can be bell-shaped. Sample functions for w.sub.n,j (i, p.sub.n,j,1, . . . , p.sub.n,j,Pn) include ##EQU2##

Modeling of Network Identification Capability.

DTIC Science & Technology

1986-07-01

3d Oa. (D .0 C 2-2 , , d .. . • . ... U9U, ’ W W w . w:. w . w L~~i...aftershock). 2. Pe p.. f. -o. p°. 𔃻 p’•.i l. mI I I + + i ..,L I + II ,,I-+ II I, qil + -]tIt -l + P ’L "P ’ "• , - . P " ",’I I"% %’ ° +"""" t...8217 % % , ’ ’,% ’. % . % ’.’ . . ’- *’-’. ’.’ . . ,° - . ...-.- " ,.."- . .. ’.. .’ -’ SSS-R-86-8033 Ile 1. Plot;’table limits i.e., the minimum ana max’mum varues of

Security clustering algorithm based on reputation in hierarchical peer-to-peer network

NASA Astrophysics Data System (ADS)

Chen, Mei; Luo, Xin; Wu, Guowen; Tan, Yang; Kita, Kenji

2013-03-01

For the security problems of the hierarchical P2P network (HPN), the paper presents a security clustering algorithm based on reputation (CABR). In the algorithm, we take the reputation mechanism for ensuring the security of transaction and use cluster for managing the reputation mechanism. In order to improve security, reduce cost of network brought by management of reputation and enhance stability of cluster, we select reputation, the historical average online time, and the network bandwidth as the basic factors of the comprehensive performance of node. Simulation results showed that the proposed algorithm improved the security, reduced the network overhead, and enhanced stability of cluster.

Binding of Amphipathic Cell Penetrating Peptide p28 to Wild Type and Mutated p53 as studied by Raman, Atomic Force and Surface Plasmon Resonance spectroscopies.

PubMed

Signorelli, Sara; Santini, Simona; Yamada, Tohru; Bizzarri, Anna Rita; Beattie, Craig W; Cannistraro, Salvatore

2017-04-01

Mutations within the DNA binding domain (DBD) of the tumor suppressor p53 are found in >50% of human cancers and may significantly modify p53 secondary structure impairing its function. p28, an amphipathic cell-penetrating peptide, binds to the DBD through hydrophobic interaction and induces a posttranslational increase in wildtype and mutant p53 restoring functionality. We use mutation analyses to explore which elements of secondary structure may be critical to p28 binding. Molecular modeling, Raman spectroscopy, Atomic Force Spectroscopy (AFS) and Surface Plasmon Resonance (SPR) were used to identify which secondary structure of site-directed and naturally occurring mutant DBDs are potentially altered by discrete changes in hydrophobicity and the molecular interaction with p28. We show that specific point mutations that alter hydrophobicity within non-mutable and mutable regions of the p53 DBD alter specific secondary structures. The affinity of p28 was positively correlated with the β-sheet content of a mutant DBD, and reduced by an increase in unstructured or random coil that resulted from a loss in hydrophobicity and redistribution of surface charge. These results help refine our knowledge of how mutations within p53-DBD alter secondary structure and provide insight on how potential structural alterations in p28 or similar molecules improve their ability to restore p53 function. Raman spectroscopy, AFS, SPR and computational modeling are useful approaches to characterize how mutations within the p53DBD potentially affect secondary structure and identify those structural elements prone to influence the binding affinity of agents designed to increase the functionality of p53. Copyright © 2017 Elsevier B.V. All rights reserved.

Context Aware Programmable Trackers for the Next Generation Internet

NASA Astrophysics Data System (ADS)

Sousa, Pedro

This work introduces and proposes the concept of context aware programmable trackers for the next generation Internet. The proposed solution gives ground for the development of advanced applications based on the P2P paradigm and will foster collaborative efforts among several network entities (e.g. P2P applications and ISPs). The proposed concept of context aware programmable trackers allows that several peer selection strategies might be supported by a P2P tracker entity able to improve the peer selection decisions according with pre-defined objectives and external inputs provided by specific services. The flexible, adaptive and enhanced peer selection semantics that might be achieved by the proposed solution will contribute for devising novel P2P based services and business models for the future Internet.

High-sensitivity pH sensor using separative extended-gate field-effect transistors with single-walled carbon-nanotube networks

NASA Astrophysics Data System (ADS)

Pyo, Ju-Young; Cho, Won-Ju

2018-04-01

We fabricate high-sensitivity pH sensors using single-walled carbon-nanotube (SWCNT) network thin-film transistors (TFTs). The sensing and transducer parts of the pH sensor are composed of separative extended-sensing gates (ESGs) with SnO2 ion-sensitive membranes and double-gate structure TFTs with thin SWCNT network channels of ∼1 nm and AlO x top-gate insulators formed by the solution-deposition method. To prevent thermal process-induced damages on the SWCNT channel layer due to the post-deposition annealing process and improve the electrical characteristics of the SWCNT-TFTs, microwave irradiation is applied at low temperatures. As a result, a pH sensitivity of 7.6 V/pH, far beyond the Nernst limit, is obtained owing to the capacitive coupling effect between the top- and bottom-gate insulators of the SWCNT-TFTs. Therefore, double-gate structure SWCNT-TFTs with separated ESGs are expected to be highly beneficial for high-sensitivity disposable biosensor applications.

A mutant p53/let-7i-axis-regulated gene network drives cell migration, invasion and metastasis

PubMed Central

Subramanian, M; Francis, P; Bilke, S; Li, XL; Hara, T; Lu, X; Jones, MF; Walker, RL; Zhu, Y; Pineda, M; Lee, C; Varanasi, L; Yang, Y; Martinez, LA; Luo, J; Ambs, S; Sharma, S; Wakefield, LM; Meltzer, PS; Lal, A

2015-01-01

Most p53 mutations in human cancers are missense mutations resulting in a full-length mutant p53 protein. Besides losing tumor suppressor activity, some hotspot p53 mutants gain oncogenic functions. This effect is mediated in part, through gene expression changes due to inhibition of p63 and p73 by mutant p53 at their target gene promoters. Here, we report that the tumor suppressor microRNA let-7i is downregulated by mutant p53 in multiple cell lines expressing endogenous mutant p53. In breast cancer patients, significantly decreased let-7i levels were associated with missense mutations in p53. Chromatin immunoprecipitation and promoter luciferase assays established let-7i as a transcriptional target of mutant p53 through p63. Introduction of let-7i to mutant p53 cells significantly inhibited migration, invasion and metastasis by repressing a network of oncogenes including E2F5, LIN28B, MYC and NRAS. Our findings demonstrate that repression of let-7i expression by mutant p53 has a key role in enhancing migration, invasion and metastasis. PMID:24662829

Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

PubMed

Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

2015-01-01

Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P-limitation responses in plants. Analysis of expression patterns of some typical P-limitation induced genes under high [CO2] suggests that long-term exposure of plants to high [CO2] would have a tendency to stimulate similar transcriptional responses as observed under P-limitation. However, studies on the combined effect of high [CO2] and low P on gene expression are scarce. Such studies would provide insights into the development of P efficient crops in the context of anticipated increases in atmospheric [CO2]. Copyright © 2015 Elsevier Inc. All rights reserved.

Architecture and dynamics of overlapped RNA regulatory networks.

PubMed

Lapointe, Christopher P; Preston, Melanie A; Wilinski, Daniel; Saunders, Harriet A J; Campbell, Zachary T; Wickens, Marvin

2017-11-01

A single protein can bind and regulate many mRNAs. Multiple proteins with similar specificities often bind and control overlapping sets of mRNAs. Yet little is known about the architecture or dynamics of overlapped networks. We focused on three proteins with similar structures and related RNA-binding specificities-Puf3p, Puf4p, and Puf5p of S. cerevisiae Using RNA Tagging, we identified a "super-network" comprised of four subnetworks: Puf3p, Puf4p, and Puf5p subnetworks, and one controlled by both Puf4p and Puf5p. The architecture of individual subnetworks, and thus the super-network, is determined by competition among particular PUF proteins to bind mRNAs, their affinities for binding elements, and the abundances of the proteins. The super-network responds dramatically: The remaining network can either expand or contract. These strikingly opposite outcomes are determined by an interplay between the relative abundance of the RNAs and proteins, and their affinities for one another. The diverse interplay between overlapping RNA-protein networks provides versatile opportunities for regulation and evolution. © 2017 Lapointe et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Biophysical characterization and crystal structure of the Feline Immunodeficiency Virus p15 matrix protein.

PubMed

Serrière, Jennifer; Robert, Xavier; Perez, Magali; Gouet, Patrice; Guillon, Christophe

2013-06-24

Feline Immunodeficiency Virus (FIV) is a viral pathogen that infects domestic cats and wild felids. During the viral replication cycle, the FIV p15 matrix protein oligomerizes to form a closed matrix that underlies the lipidic envelope of the virion. Because of its crucial role in the early and late stages of viral morphogenesis, especially in viral assembly, FIV p15 is an interesting target in the development of potential new therapeutic strategies. Our biochemical study of FIV p15 revealed that it forms a stable dimer in solution under acidic conditions and at high concentration, unlike other retroviral matrix proteins. We determined the crystal structure of full-length FIV p15 to 2 Å resolution and observed a helical organization of the protein, typical for retroviral matrix proteins. A hydrophobic pocket that could accommodate a myristoyl group was identified, and the C-terminal end of FIV p15, which is mainly unstructured, was visible in electron density maps. As FIV p15 crystallizes in acidic conditions but with one monomer in the asymmetric unit, we searched for the presence of a biological dimer in the crystal. No biological assembly was detected by the PISA server, but the three most buried crystallographic interfaces have interesting features: the first one displays a highly conserved tryptophan acting as a binding platform, the second one is located along a 2-fold symmetry axis and the third one resembles the dimeric interface of EIAV p15. Because the C-terminal end of p15 is involved in two of these three interfaces, we investigated the structure and assembly of a C-terminal-truncated form of p15 lacking 14 residues. The truncated FIV p15 dimerizes in solution at a lower concentration and crystallizes with two molecules in the asymmetric unit. The EIAV-like dimeric interface is the only one to be retained in the new crystal form. The dimeric form of FIV p15 in solution and its extended C-terminal end are characteristic among lentiviral matrix proteins. Crystallographic interfaces revealed several interactions that might be involved in FIV replication. Further studies are needed to better understand their biological relevance in the function of FIV Gag during viral replication.

Neuronal correlates of a virtual-reality-based passive sensory P300 network.

PubMed

Chen, Chun-Chuan; Syue, Kai-Syun; Li, Kai-Chiun; Yeh, Shih-Ching

2014-01-01

P300, a positive event-related potential (ERP) evoked at around 300 ms after stimulus, can be elicited using an active or passive oddball paradigm. Active P300 requires a person's intentional response, whereas passive P300 does not require an intentional response. Passive P300 has been used in incommunicative patients for consciousness detection and brain computer interface. Active and passive P300 differ in amplitude, but not in latency or scalp distribution. However, no study has addressed the mechanism underlying the production of passive P300. In particular, it remains unclear whether the passive P300 shares an identical active P300 generating network architecture when no response is required. This study aims to explore the hierarchical network of passive sensory P300 production using dynamic causal modelling (DCM) for ERP and a novel virtual reality (VR)-based passive oddball paradigm. Moreover, we investigated the causal relationship of this passive P300 network and the changes in connection strength to address the possible functional roles. A classical ERP analysis was performed to verify that the proposed VR-based game can reliably elicit passive P300. The DCM results suggested that the passive and active P300 share the same parietal-frontal neural network for attentional control and, underlying the passive network, the feed-forward modulation is stronger than the feed-back one. The functional role of this forward modulation may indicate the delivery of sensory information, automatic detection of differences, and stimulus-driven attentional processes involved in performing this passive task. To our best knowledge, this is the first study to address the passive P300 network. The results of this study may provide a reference for future clinical studies on addressing the network alternations under pathological states of incommunicative patients. However, caution is required when comparing patients' analytic results with this study. For example, the task presented here is not applicable to incommunicative patients.

Neuronal Correlates of a Virtual-Reality-Based Passive Sensory P300 Network

PubMed Central

Chen, Chun-Chuan; Syue, Kai-Syun; Li, Kai-Chiun; Yeh, Shih-Ching

2014-01-01

P300, a positive event-related potential (ERP) evoked at around 300 ms after stimulus, can be elicited using an active or passive oddball paradigm. Active P300 requires a person’s intentional response, whereas passive P300 does not require an intentional response. Passive P300 has been used in incommunicative patients for consciousness detection and brain computer interface. Active and passive P300 differ in amplitude, but not in latency or scalp distribution. However, no study has addressed the mechanism underlying the production of passive P300. In particular, it remains unclear whether the passive P300 shares an identical active P300 generating network architecture when no response is required. This study aims to explore the hierarchical network of passive sensory P300 production using dynamic causal modelling (DCM) for ERP and a novel virtual reality (VR)-based passive oddball paradigm. Moreover, we investigated the causal relationship of this passive P300 network and the changes in connection strength to address the possible functional roles. A classical ERP analysis was performed to verify that the proposed VR-based game can reliably elicit passive P300. The DCM results suggested that the passive and active P300 share the same parietal-frontal neural network for attentional control and, underlying the passive network, the feed-forward modulation is stronger than the feed-back one. The functional role of this forward modulation may indicate the delivery of sensory information, automatic detection of differences, and stimulus-driven attentional processes involved in performing this passive task. To our best knowledge, this is the first study to address the passive P300 network. The results of this study may provide a reference for future clinical studies on addressing the network alternations under pathological states of incommunicative patients. However, caution is required when comparing patients’ analytic results with this study. For example, the task presented here is not applicable to incommunicative patients. PMID:25401520

Structural polymorphism of a cytosine-rich DNA sequence forming i-motif structure: Exploring pH based biosensors.

PubMed

Ahmed, Saami; Kaushik, Mahima; Chaudhary, Swati; Kukreti, Shrikant

2018-05-01

Sequence recognition and conformational polymorphism enable DNA to emerge out as a substantial tool in fabricating the devices within nano-dimensions. These DNA associated nano devices work on the principle of conformational switches, which can be facilitated by many factors like sequence of DNA/RNA strand, change in pH or temperature, enzyme or ligand interactions etc. Thus, controlling these DNA conformational changes to acquire the desired function is significant for evolving DNA hybridization biosensor, used in genetic screening and molecular diagnosis. For exploring this conformational switching ability of cytosine-rich DNA oligonucleotides as a function of pH for their potential usage as biosensors, this study has been designed. A C-rich stretch of DNA sequence (5'-TCCCCCAATTAATTCCCCCA-3'; SG20c) has been investigated using UV-Thermal denaturation, poly-acrylamide gel electrophoresis and CD spectroscopy. The SG20c sequence is shown to adopt various topologies of i-motif structure at low pH. This pH dependent transition of SG20c from unstructured single strand to unimolecular and bimolecular i-motif structures can further be exploited for its utilization as switching on/off pH-based biosensors. Copyright © 2018. Published by Elsevier B.V.

Silver indium diphosphate, AgInP(2)O(7).

PubMed

Zouihri, Hafid; Saadi, Mohamed; Jaber, Boujemaa; El Ammari, Lehcen

2010-12-18

Polycrystalline material of the title compound, AgInP(2)O(7), was synthesized by traditional high-temperature solid-state methods and single crystals were grown from the melt of a mixture of AgInP(2)O(7) and B(2)O(3) as flux in a platinium crucible. The structure consists of InO(6) octa-hedra, which are corner-shared to PO(4) tetra-hedra into a three-dimensional network with hexa-gonal channels running parallel to the c axis. The silver cation, located in the channel, is bonded to seven O atoms of the [InP(2)O(7)] framework with Ag-O distances ranging from 2.370 (2) to 3.015 (2) Å. The P(2)O(7) diphosphate anion is characterized by a P-O-P angle of 137.27 (9) and a nearly eclipsed conformation. AgInP(2)O(7) is isotypic with the M(I)FeP(2)O(7) (M(I) = Na, K, Rb, Cs and Ag) diphosphate family.

White matter tract network disruption explains reduced conscientiousness in multiple sclerosis.

PubMed

Fuchs, Tom A; Dwyer, Michael G; Kuceyeski, Amy; Choudhery, Sanjeevani; Carolus, Keith; Li, Xian; Mallory, Matthew; Weinstock-Guttman, Bianca; Jakimovski, Dejan; Ramasamy, Deepa; Zivadinov, Robert; Benedict, Ralph H B

2018-05-08

Quantifying white matter (WM) tract disruption in people with multiple sclerosis (PwMS) provides a novel means for investigating the relationship between defective network connectivity and clinical markers. PwMS exhibit perturbations in personality, where decreased Conscientiousness is particularly prominent. This trait deficit influences disease trajectory and functional outcomes such as work capacity. We aimed to identify patterns of WM tract disruption related to decreased Conscientiousness in PwMS. Personality assessment and brain MRI were obtained in 133 PwMS and 49 age- and sex-matched healthy controls (HC). Lesion maps were applied to determine the severity of WM tract disruption between pairs of gray matter regions. Next, the Network-Based-Statistics tool was applied to identify structural networks whose disruption negatively correlates with Conscientiousness. Finally, to determine whether these networks explain unique variance above conventional MRI measures and cognition, regression models were applied controlling for age, sex, brain volume, T2-lesion volume, and cognition. Relative to HCs, PwMS exhibited lower Conscientiousness and slowed cognitive processing speed (p = .025, p = .006). Lower Conscientiousness in PwMS was significantly associated with WM tract disruption between frontal, frontal-parietal, and frontal-cingulate pathways in the left (p = .02) and right (p = .01) hemisphere. The mean disruption of these pathways explained unique additive variance in Conscientiousness, after accounting for conventional MRI markers of pathology and cognition (ΔR 2  = .049, p = .029). Damage to WM tracts between frontal, frontal-parietal, and frontal-cingulate cortical regions is significantly correlated with reduced Conscientiousness in PwMS. Tract disruption within these networks explains decreased Conscientiousness observed in PwMS as compared with HCs. © 2018 Wiley Periodicals, Inc.

Hypoxia induces a phase transition within a kinase signaling network in cancer cells

PubMed Central

Wei, Wei; Shi, Qihui; Remacle, Francoise; Qin, Lidong; Shackelford, David B.; Shin, Young Shik; Mischel, Paul S.; Levine, R. D.; Heath, James R.

2013-01-01

Hypoxia is a near-universal feature of cancer, promoting glycolysis, cellular proliferation, and angiogenesis. The molecular mechanisms of hypoxic signaling have been intensively studied, but the impact of changes in oxygen partial pressure (pO2) on the state of signaling networks is less clear. In a glioblastoma multiforme (GBM) cancer cell model, we examined the response of signaling networks to targeted pathway inhibition between 21% and 1% pO2. We used a microchip technology that facilitates quantification of a panel of functional proteins from statistical numbers of single cells. We find that near 1.5% pO2, the signaling network associated with mammalian target of rapamycin (mTOR) complex 1 (mTORC1)—a critical component of hypoxic signaling and a compelling cancer drug target—is deregulated in a manner such that it will be unresponsive to mTOR kinase inhibitors near 1.5% pO2, but will respond at higher or lower pO2 values. These predictions were validated through experiments on bulk GBM cell line cultures and on neurosphere cultures of a human-origin GBM xenograft tumor. We attempt to understand this behavior through the use of a quantitative version of Le Chatelier’s principle, as well as through a steady-state kinetic model of protein interactions, both of which indicate that hypoxia can influence mTORC1 signaling as a switch. The Le Chatelier approach also indicates that this switch may be thought of as a type of phase transition. Our analysis indicates that certain biologically complex cell behaviors may be understood using fundamental, thermodynamics-motivated principles. PMID:23530221

Logical optical line terminal technologies towards flexible and highly reliable metro- and access-integrated networks

NASA Astrophysics Data System (ADS)

Okamoto, Satoru; Sato, Takehiro; Yamanaka, Naoaki

2017-01-01

In this paper, flexible and highly reliable metro and access integrated networks with network virtualization and software defined networking technologies will be presented. Logical optical line terminal (L-OLT) technologies and active optical distribution networks (ODNs) are the key to introduce flexibility and high reliability into the metro and access integrated networks. In the Elastic Lambda Aggregation Network (EλAN) project which was started in 2012, a concept of the programmable optical line terminal (P-OLT) has been proposed. A role of the P-OLT is providing multiple network services that have different protocols and quality of service requirements by single OLT box. Accommodated services will be Internet access, mobile front-haul/back-haul, data-center access, and leased line. L-OLTs are configured within the P-OLT box to support the functions required for each network service. Multiple P-OLTs and programmable optical network units (P-ONUs) are connected by the active ODN. Optical access paths which have flexible capacity are set on the ODN to provide network services from L-OLT to logical ONUs (L-ONUs). The L-OLT to L-ONU path on the active ODN provides a logical connection. Therefore, introducing virtualization technologies becomes possible. One example is moving an L-OLT from one P-OLT to another P-OLT like a virtual machine. This movement is called L-OLT migration. The L-OLT migration provides flexible and reliable network functions such as energy saving by aggregating L-OLTs to a limited number of P-OLTs, and network wide optical access path restoration. Other L-OLT virtualization technologies and experimental results will be also discussed in the paper.

Evaluation of a Prototype pCO2 Optical Sensor

NASA Astrophysics Data System (ADS)

Sanborn-Marsh, C.; Sutton, A.; Sabine, C. L.; Lawrence-Salvas, N.; Dietrich, C.

2016-12-01

Anthropogenic greenhouse gas emissions continue to rise, driving climate change and altering the ocean carbonate systems. Carbonate chemistry can be characterized by any two of the four parameters: pH, total alkalinity, dissolved inorganic carbon, and partial pressure of dissolved carbon dioxide gas (pCO2). To fully monitor these dynamic systems, researchers must deploy a more temporally and spatially comprehensive sensor network. Logistical challenges, such as the energy consumption, size, lifetime, depth range, and cost of pCO2 sensors have limited the network's reach so far. NOAA's Pacific Marine Environmental Laboratory has conducted assessment tests of a pCO2 optical sensor (optode), recently developed by Atamanchuk et al (2014). We hope to deploy this optode in the summer of 2017 on high-resolution moored profiler, along with temperature, salinity, and oxygen sensors. While most pCO2 optodes have energy consumptions of 3-10 W, this 36mm-diameter by 86mm-long instrument consumes a mere 7-80 mW. Initial testing showed that its accuracy varied within an absolute range of 2-75 μatm, depending on environmental conditions, including temperature, salinity, response time, and initial calibration. Further research independently examining the effects of each variable on the accuracy of the data will also be presented.

[Benefit of network education to college students' knowledge about sexual and reproductive health in Ningbo city].

PubMed

Wang, Guo-yao; Ji, Yun-xin; Ding, Hui-qing; Gui, Zhong-bao; Liang, Xiao-ming; Fu, Jian-fei; Cheng, Yue

2015-12-01

To investigate how network education can improve college students' knowledge on sexual and reproductive health in Ningbo city. From December 2012 to June 2013, we conducted a questionnaire investigation among college students in Ningbo city about the effects of network education on their knowledge about sexual psychology, sexual physiology, sexual ethics, and reproductive health. A total of 7 362 college students accomplished the investigation, of whom 2 483 (42.1% males and 57.9% females) received network education, while the other 4 879 (24.1% males and 75.9% females) did not. Approximately 47.1% of the male and 28.0% of the female students acquired sexual and reproductive knowledge via network education. Reproductive health-related network education significantly enriched the students' knowledge about the reproductive system and sex, pubertal development, sexual physiology, conception and embryonic development, methods of contraception, sexual psychology, sexually transmitted diseases and their prevention, pregnancy care and eugenics, and environment- and occupation-related reproductive health (P < 0.01). It also remarkably improved their cognitive attitude towards reproductive health knowledge (P < 0.01). Those who received reproductive health-related network education showed a significantly higher rate of masturbation (P < 0.01) but markedly later time of the first masturbation (P < 0.01) than those who did not. Network education can enhance the effect of reproductive health education among college students and improve their sexual experience and health.

Frontal parietal control network regulates the anti-correlated default and dorsal attention networks.

PubMed

Gao, Wei; Lin, Weili

2012-01-01

Recent reports demonstrate the anti-correlated behaviors between the default (DF) and the dorsal attention (DA) networks. We aimed to investigate the roles of the frontal parietal control (FPC) network in regulating the two anti-correlated networks through three experimental conditions, including resting, continuous self-paced/attended sequential finger tapping (FT), and natural movie watching (MW), respectively. The two goal-directed tasks were chosen to engage either one of the two competing networks-FT for DA whereas MW for default. We hypothesized that FPC will selectively augment/suppress either network depending on how the task targets the specific network; FPC will positively correlate with the target network, but negatively correlate with the network anti-correlated with the target network. We further hypothesized that significant causal links from FPC to both DA and DF are present during all three experimental conditions, supporting the initiative regulating role of FPC over the two opposing systems. Consistent with our hypotheses, FPC exhibited a significantly higher positive correlation with DA (P = 0.0095) whereas significantly more negative correlation with default (P = 0.0025) during FT when compared to resting. Completely opposite to that observed during FT, the FPC was significantly anti-correlated with DA (P = 2.1e-6) whereas positively correlated with default (P = 0.0035) during MW. Furthermore, extensive causal links from FPC to both DA and DF were observed across all three experimental states. Together, our results strongly support the notion that the FPC regulates the anti-correlated default and DA networks. Copyright © 2011 Wiley Periodicals, Inc.

The Optimal Timing of Stage 2 Palliation for Hypoplastic Left Heart Syndrome: An Analysis of the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Data Set.

PubMed

Meza, James M; Hickey, Edward J; Blackstone, Eugene H; Jaquiss, Robert D B; Anderson, Brett R; Williams, William G; Cai, Sally; Van Arsdell, Glen S; Karamlou, Tara; McCrindle, Brian W

2017-10-31

In infants requiring 3-stage single-ventricle palliation for hypoplastic left heart syndrome, attrition after the Norwood procedure remains significant. The effect of the timing of stage 2 palliation (S2P), a physician-modifiable factor, on long-term survival is not well understood. We hypothesized that an optimal interval between the Norwood and S2P that both minimizes pre-S2P attrition and maximizes post-S2P survival exists and is associated with individual patient characteristics. The National Institutes of Health/National Heart, Lung, and Blood Institute Pediatric Heart Network Single Ventricle Reconstruction Trial public data set was used. Transplant-free survival (TFS) was modeled from (1) Norwood to S2P and (2) S2P to 3 years by using parametric hazard analysis. Factors associated with death or heart transplantation were determined for each interval. To account for staged procedures, risk-adjusted, 3-year, post-Norwood TFS (the probability of TFS at 3 years given survival to S2P) was calculated using parametric conditional survival analysis. TFS from the Norwood to S2P was first predicted. TFS after S2P to 3 years was then predicted and adjusted for attrition before S2P by multiplying by the estimate of TFS to S2P. The optimal timing of S2P was determined by generating nomograms of risk-adjusted, 3-year, post-Norwood, TFS versus the interval from the Norwood to S2P. Of 547 included patients, 399 survived to S2P (73%). Of the survivors to S2P, 349 (87%) survived to 3-year follow-up. The median interval from the Norwood to S2P was 5.1 (interquartile range, 4.1-6.0) months. The risk-adjusted, 3-year, TFS was 68±7%. A Norwood-S2P interval of 3 to 6 months was associated with greatest 3-year TFS overall and in patients with few risk factors. In patients with multiple risk factors, TFS was severely compromised, regardless of the timing of S2P and most severely when S2P was performed early. No difference in the optimal timing of S2P existed when stratified by shunt type. In infants with few risk factors, progressing to S2P at 3 to 6 months after the Norwood procedure was associated with maximal TFS. Early S2P did not rescue patients with greater risk factor burdens. Instead, referral for heart transplantation may offer their best chance at long-term survival. URL: https://www.clinicaltrials.gov. Unique identifier: NCT00115934. © 2017 American Heart Association, Inc.

When perceptions defy reality: The relationships between depression and actual and perceived Facebook social support.

PubMed

Park, Jiyoung; Lee, David Seungjae; Shablack, Holly; Verduyn, Philippe; Deldin, Patricia; Ybarra, Oscar; Jonides, John; Kross, Ethan

2016-08-01

Although the relationship between depression and "offline" social support is well established, numerous questions surround the relationship between "online" social support and depression. We explored this issue by examining the social support dynamics that characterize the way individuals with varying levels of depression (Study 1) and SCID-diagnosed clinically depressed and non-depressed individuals (Study 2) interact with Facebook, the world's largest online social network. Using a novel methodology, we examined how disclosing positive or negative information on Facebook influences the amount of social support depressed individuals (a) actually receive (based on actual social support transactions recorded on Facebook walls) and (b) think they receive (based on subjective assessments) from their Facebook network. Contrary to prior research indicating that depression correlates with less actual social support from "offline" networks, across both studies depression was positively correlated with social support from Facebook networks when participants disclosed negative information (p=.02 in Study 1 and p=.06 in Study 2). Yet, depression was negatively correlated with how much social support participants thought they received from their Facebook networks (p=.005 in Study 1 and p=.001 in Study 2). The sample size was relatively small in Study 2, reflecting difficulties of recruiting individuals with Major Depressive Disorder. These results demonstrate that an asymmetry characterizes the relationship between depression and different types of Facebook social support and further identify perceptions of Facebook social support as a potential intervention target. (243 words; 250 max). Copyright © 2016 Elsevier B.V. All rights reserved.

A Simulated Intermediate State for Folding and Aggregation Provides Insights into ΔN6 β2-Microglobulin Amyloidogenic Behavior

PubMed Central

Estácio, Sílvia G.; Krobath, Heinrich; Vila-Viçosa, Diogo; Machuqueiro, Miguel; Shakhnovich, Eugene I.; Faísca, Patrícia F. N.

2014-01-01

A major component of ex vivo amyloid plaques of patients with dialysis-related amyloidosis (DRA) is a cleaved variant of β2-microglobulin (ΔN6) lacking the first six N-terminal residues. Here we perform a computational study on ΔN6, which provides clues to understand the amyloidogenicity of the full-length β2-microglobulin. Contrary to the wild-type form, ΔN6 is able to efficiently nucleate fibrillogenesis in vitro at physiological pH. This behavior is enhanced by a mild acidification of the medium such as that occurring in the synovial fluid of DRA patients. Results reported in this work, based on molecular simulations, indicate that deletion of the N-terminal hexapeptide triggers the formation of an intermediate state for folding and aggregation with an unstructured strand A and a native-like core. Strand A plays a pivotal role in aggregation by acting as a sticky hook in dimer assembly. This study further predicts that the detachment of strand A from the core is maximized at pH 6.2 resulting into higher aggregation efficiency. The structural mapping of the dimerization interface suggests that Tyr10, His13, Phe30 and His84 are hot-spot residues in ΔN6 amyloidogenesis. PMID:24809460

High-Reproducibility and High-Accuracy Method for Automated Topic Classification

NASA Astrophysics Data System (ADS)

Lancichinetti, Andrea; Sirer, M. Irmak; Wang, Jane X.; Acuna, Daniel; Körding, Konrad; Amaral, Luís A. Nunes

2015-01-01

Much of human knowledge sits in large databases of unstructured text. Leveraging this knowledge requires algorithms that extract and record metadata on unstructured text documents. Assigning topics to documents will enable intelligent searching, statistical characterization, and meaningful classification. Latent Dirichlet allocation (LDA) is the state of the art in topic modeling. Here, we perform a systematic theoretical and numerical analysis that demonstrates that current optimization techniques for LDA often yield results that are not accurate in inferring the most suitable model parameters. Adapting approaches from community detection in networks, we propose a new algorithm that displays high reproducibility and high accuracy and also has high computational efficiency. We apply it to a large set of documents in the English Wikipedia and reveal its hierarchical structure.

TWSTFT Network Status in the Pacific Rim Region and Development of a New Time Transfer Modem for TWSTFT

DTIC Science & Technology

2000-01-01

32nd Annual Precise T ime and Time Interval ( P T T I ) Meeting TWSTFT NETWORK STATUS IN THE PACIFIC RIM REGION AND DEVELOPMENT OF A NEW TIME...TRANSFER MODEM FOR TWSTFT M. Imael, M. Hosokawal, Y . Hanadol, 2. Li2, P. Fisk3, Y . Nakadan4, and C. S. Liao5 ’Communications Research Laboratory...Metrology (NRLM), Japan 5Telecommunication Laboratories (TL) , Taipei, Taiwan Abstract Iko-Way Satellite Time and Frequency Transfer ( TWSTFT ) is one

Systems biology and the origins of life? part II. Are biochemical networks possible ancestors of living systems? networks of catalysed chemical reactions: non-equilibrium, self-organization and evolution.

PubMed

Ricard, Jacques

2010-01-01

The present article discusses the possibility that catalysed chemical networks can evolve. Even simple enzyme-catalysed chemical reactions can display this property. The example studied is that of a two-substrate proteinoid, or enzyme, reaction displaying random binding of its substrates A and B. The fundamental property of such a system is to display either emergence or integration depending on the respective values of the probabilities that the enzyme has bound one of its substrate regardless it has bound the other substrate, or, specifically, after it has bound the other substrate. There is emergence of information if p(A)>p(AB) and p(B)>p(BA). Conversely, if p(A)

Network Dynamics: Modeling And Generation Of Very Large Heterogeneous Social Networks

DTIC Science & Technology

2015-11-23

P11035 (2014). [19] P. L. Krapivsky and S. Redner, Phys. Rev. E. 71, 036118 (2005). [20] M. O. Jackson and B. W. Rogers, Amer. Econ . Rev. 97, 890...P06004 (2010). [24] M. E. J. Newman, Networks: An Introduction (Oxford Univ. Press, Oxford, 2010). [25] P. J. Flory, Principles of Polymer Chemistry

Network Influences on the Sexual Risk Behaviors of Gay, Bisexual and Other Men Who Have Sex with Men Using Geosocial Networking Applications.

PubMed

Holloway, Ian W; Pulsipher, Craig A; Gibbs, Jeremy; Barman-Adhikari, Anamika; Rice, Eric

2015-06-01

Geosocial networking applications (GSN apps) have become increasingly popular among gay, bisexual and other men who have sex with men (MSM). Our study sought to understand whether inclusion of individuals met via GSN apps in participants' social networks was associated with increased HIV risk behaviors among a probability sample of GSN app using MSM (N = 295) recruited in Los Angeles, California. Approximately 20 % of participants included a GSN app-met individual as one of their top five closest social network members. Those with a GSN app-met network member had more recent (past 30-day) sexual partners (B = 1.21, p < 0.05), were nearly twice as likely to have engaged in unprotected anal intercourse (UAI) with their last sexual partner (AOR = 2.02, p < 0.05), and were nearly four times as likely to have engaged in UAI with their last GSN app-met sexual partner (AOR = 3.98, p < 0.001). Network-based interventions delivered via GSN apps may be useful in preventing the spread of HIV among MSM.

Network Influences on the Sexual Risk Behaviors of Gay, Bisexual and Other Men Who Have Sex With Men Using Geosocial Networking Applications

PubMed Central

Holloway, Ian W.; Pulsipher, Craig A.; Gibbs, Jeremy; Barman-Adhikari, Anamika; Rice, Eric

2016-01-01

Geosocial networking applications (GSN apps) have become increasingly popular among gay, bisexual and other men who have sex with men (MSM). Our study sought to understand whether inclusion of individuals met via GSN apps in participants’ social networks was associated with increased HIV risk behaviors among a probability sample of GSN app using MSM (N=295) recruited in Los Angeles, California. Approximately 20% of participants included a GSN app-met individual as one of their top five closest social network members. Those with a GSN app-met network member had more recent (past 30-day) sexual partners (B=1.21, p<0.05), were nearly twice as likely to have engaged in unprotected anal intercourse (UAI) with their last sexual partner (AOR=2.02, p<0.05), and were nearly four times as likely to have engaged in UAI with their last GSN app-met sexual partner (AOR=3.98, p<0.001). Network-based interventions delivered via GSN apps may be useful in preventing the spread of HIV among MSM. PMID:25572832

Numerical modeling of landslide-generated tsunami using adaptive unstructured meshes

NASA Astrophysics Data System (ADS)

Wilson, Cian; Collins, Gareth; Desousa Costa, Patrick; Piggott, Matthew

2010-05-01

Landslides impacting into or occurring under water generate waves, which can have devastating environmental consequences. Depending on the characteristics of the landslide the waves can have significant amplitude and potentially propagate over large distances. Linear models of classical earthquake-generated tsunamis cannot reproduce the highly nonlinear generation mechanisms required to accurately predict the consequences of landslide-generated tsunamis. Also, laboratory-scale experimental investigation is limited to simple geometries and short time-scales before wave reflections contaminate the data. Computational fluid dynamics models based on the nonlinear Navier-Stokes equations can simulate landslide-tsunami generation at realistic scales. However, traditional chessboard-like structured meshes introduce superfluous resolution and hence the computing power required for such a simulation can be prohibitively high, especially in three dimensions. Unstructured meshes allow the grid spacing to vary rapidly from high resolution in the vicinity of small scale features to much coarser, lower resolution in other areas. Combining this variable resolution with dynamic mesh adaptivity allows such high resolution zones to follow features like the interface between the landslide and the water whilst minimising the computational costs. Unstructured meshes are also better suited to representing complex geometries and bathymetries allowing more realistic domains to be simulated. Modelling multiple materials, like water, air and a landslide, on an unstructured adaptive mesh poses significant numerical challenges. Novel methods of interface preservation must be considered and coupled to a flow model in such a way that ensures conservation of the different materials. Furthermore this conservation property must be maintained during successive stages of mesh optimisation and interpolation. In this paper we validate a new multi-material adaptive unstructured fluid dynamics model against the well-known Lituya Bay landslide-generated wave experiment and case study [1]. In addition, we explore the effect of physical parameters, such as the shape, velocity and viscosity of the landslide, on wave amplitude and run-up, to quantify their influence on the landslide-tsunami hazard. As well as reproducing the experimental results, the model is shown to have excellent conservation and bounding properties. It also requires fewer nodes than an equivalent resolution fixed mesh simulation, therefore minimising at least one aspect of the computational cost. These computational savings are directly transferable to higher dimensions and some initial three dimensional results are also presented. These reproduce the experiments of DiRisio et al. [2], where an 80cm long landslide analogue was released from the side of an 8.9m diameter conical island in a 50 × 30m tank of water. The resulting impact between the landslide and the water generated waves with an amplitude of 1cm at wave gauges around the island. The range of scales that must be considered in any attempt to numerically reproduce this experiment makes it an ideal case study for our multi-material adaptive unstructured fluid dynamics model. [1] FRITZ, H. M., MOHAMMED, F., & YOO, J. 2009. Lituya Bay Landslide Impact Generated Mega-Tsunami 50th Anniversary. Pure and Applied Geophysics, 166(1), 153-175. [2] DIRISIO, M., DEGIROLAMO, P., BELLOTTI, G., PANIZZO, A., ARISTODEMO, F.,

Effect of oxygen on the optical, electrical and structural properties of mixed-phase boron doped nanocrystalline silicon oxide thin films

NASA Astrophysics Data System (ADS)

Das, Debajyoti; Mondal, Praloy

2017-11-01

Systematic investigation on the optoelectronic and structural changes occurring in the p-nc-Si network due to the inclusion of oxygen into the initial crystalline-like matrix has been done. The incorporation of O into the Si network occurs via the Si-O-Si bond which is effectively responsible for the widening of optical band gap. B incorporation takes place via the B-Si bonds as well as the B-O bonds which increases at enhanced CO2 dilution to the plasma. The continuously increased intensity of (SiH2)n wagging and Si-H2 bending mode in p-nc-SiOx films indicates poly-hydrogenation as inherent to the increasing oxygen alloying of the network. Two stage activation energies across around 340 K in the temperature dependent dark conductivity identify prominent two phase structure of the p-nc-SiOx material, the Si-ncs being embedded within amorphous p-SiOx matrix. The p-nc-SiOx film grown by typical 13.56 MHz PE-CVD at a low growth temperature ∼170 °C and optimized with a convincingly good combination of the electrical conductivity (σD ∼6.8 × 10-2 S cm-1), optical band gap (Eg ∼1.91 eV) and volume fraction (XC ∼54%) of the Si crystallinity containing CH <6 at% and CO < 1 at%, emerges highly competent for effective utilization in the window layer of nc-Si p-i-n solar cells with superstrate configuration.

Healthy Lifestyle Fitness Camp: A Summer Approach to Prevent Obesity in Low-Income Youth.

PubMed

George, Gretchen Lynn; Schneider, Constance; Kaiser, Lucia

2016-03-01

To examine the effect of participation in a summer camp focused on nutrition and fitness among low-income youth. In 2011-2012, overweight and obese youth (n = 126) from Fresno, CA participated in a free 6-week summer program, Healthy Lifestyle Fitness Camp (HLFC), which included 3 h/wk of nutrition education provided by University of California CalFresh and 3 hours of daily physical activity through Fresno Parks and Recreation. The researchers used repeated-measures ANOVA to examine changes in weight, waist circumference, and waist-to-height ratio (WHtR) between HLFC and the comparison group (n = 29). Significant pre-post WHtR reductions were observed in HLFC: 0.64 to 0.61 (P < .001). In addition, WHtR reductions were maintained in HLFC 2 months afterward whereas an increase occurred in the comparison group (P < .007). Understanding the impact of nutrition- and fitness-themed summer camps during unstructured months of summer is integral to obesity prevention among low-income youth. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Toxoplasmosis Titers and past Suicide Attempts Among Older Adolescents Initiating SSRI Treatment.

PubMed

Coryell, William; Yolken, Robert; Butcher, Brandon; Burns, Trudy; Dindo, Lilian; Schlechte, Janet; Calarge, Chadi

2016-01-01

Latent infection with toxoplasmosis is a prevalent condition that has been linked in animal studies to high-risk behaviors, and in humans, to suicide and suicide attempts. This analysis investigated a relationship between suicide attempt history and toxoplasmosis titers in a group of older adolescents who had recently begun treatment with an SSRI. Of 108 participants, 17 (15.7 %) had a lifetime history of at least one suicide attempt. All were given structured and unstructured diagnostic interviews and provided blood samples. Two individuals (11.9%) with a past suicide attempt, and two (2.1%) without this history, had toxoplasmosis titers ≥ 10 IU/ml (p = 0.166). Those with a past suicide attempt had mean toxoplasmosis titers that were significantly different (p = 0.018) from those of patients who lacked this history. An ROC analysis suggested a lower optimal threshold for distinguishing patients with and without suicide attempts (3.6 IU/ml) than that customarily used to identify seropositivity. Toxoplasmosis titers may quantify a proneness to suicidal behavior in younger individuals being treated with antidepressants.

Frontal Parietal Control Network Regulates the Anti-Correlated Default and Dorsal Attention Networks

PubMed Central

Gao, Wei; Lin, Weili

2011-01-01

Recent reports demonstrate the anti-correlated behaviors between the default and the dorsal attention (DA) networks. We aimed to investigate the roles of the frontal parietal control (FPC) network in regulating the two anti-correlated networks through three experimental conditions, including resting, continuous self-paced/attended sequential finger tapping (FT), and natural movie watching (MW), respectively. The two goal-directed tasks were chosen to engage either one of the two competing networks—FT for DA whereas MW for default. We hypothesized that FPC will selectively augment/suppress either network depending on how the task targets the specific network; FPC will positively correlate with the target network, but negatively correlate with the network anti-correlated with the target network. We further hypothesized that significant causal links from FPC to both DA and DF are present during all three experimental conditions, supporting the initiative regulating role of FPC over the two opposing systems. Consistent with our hypotheses, FPC exhibited a significantly higher positive correlation with DA (P = 0.0095) whereas significantly more negative correlation with default (P = 0.0025) during FT when compared to resting. Completely opposite to that observed during FT, the FPC was significantly anti-correlated with DA (P = 2.1e-6) whereas positively correlated with default (P = 0.0035) during MW. Furthermore, extensive causal links from FPC to both DA and DF were observed across all three experimental states. Together, our results strongly support the notion that the FPC regulates the anti-correlated default and DA networks. PMID:21391263

Improved mb-Ms Discrimination Using mb(P-coda) and MsU with Application to the Six North Korean Nuclear Tests

NASA Astrophysics Data System (ADS)

Napoli, V.; Yoo, S. H.; Russell, D. R.

2017-12-01

To improve discrimination of small explosions and earthquakes, we developed a new magnitude scale based on the standard Ms:mb discrimination method. In place of 20 second Ms measurements we developed a unified Rayleigh and Love wave magnitude scale (MsU) that is designed to maximize available information from single stations and then combine magnitude estimates into network averages. Additionally, in place of mb(P) measurements we developed an mb(P-Coda) magnitude scale as the properties of the coda make sparse network mb(P-Coda) more robust and less variable than network mb(P) estimates. A previous mb:MsU study conducted in 2013 in the Korean Peninsula shows that the use of MsU in place of standard 20 second Ms, leads to increased population separation and reduced scattering. The goals of a combined mb(P-coda):MsU scale are reducing scatter, ensuring applicability at small magnitudes with sparse networks, and improving the overall distribution for mb:Ms earthquake and explosion populations. To test this method we are calculating mb(P-coda)and MsU for a catalog earthquakes located in and near the Korean Peninsula, for the six North Korean nuclear tests (4.1 < mb < 6.3) and for the 3 aftershocks to date that occurred after the sixth test (2.6 < ML < 4.0). Compared to the previous 2013 study, we expect to see greater separation in the populations and less scattering with the inclusion of mb(P-coda) and with the implementation of additional filters for MsU to improve signal-to-noise levels; this includes S-transform filtering for polarization and off-azimuth signal reduction at regional distances. As we are expanding our database of mb(P-coda):MsU measurements in the Korean Peninsula to determine the earthquake and explosion distribution, this research will address the limitations and potential for discriminating small magnitude events using sparse networks.

NMR studies of the backbone flexibility and structure of human growth hormone: a comparison of high and low pH conformations.

PubMed

Kasimova, Marina R; Kristensen, Søren M; Howe, Peter W A; Christensen, Thorkild; Matthiesen, Finn; Petersen, Jørgen; Sørensen, Hans H; Led, Jens J

2002-05-03

(15)N NMR relaxation parameters and amide (1)H/(2)H-exchange rates have been used to characterize the structural flexibility of human growth hormone (rhGH) at neutral and acidic pH. Our results show that the rigidity of the molecule is strongly affected by the solution conditions. At pH 7.0 the backbone dynamics parameters of rhGH are uniform along the polypeptide chain and their values are similar to those of other folded proteins. In contrast, at pH 2.7 the overall backbone flexibility increases substantially compared to neutral pH and the average order parameter approaches the lower limit expected for a folded protein. However, a significant variation of the backbone dynamics through the molecule indicates that under acidic conditions the mobility of the residues becomes more dependent on their location within the secondary structure units. In particular, the order parameters of certain loop regions decrease dramatically and become comparable to those found in unfolded proteins. Furthermore, the HN-exchange rates at low pH reveal that the residues most protected from exchange are clustered at one end of the helical bundle, forming a stable nucleus. We suggest that this nucleus maintains the overall fold of the protein under destabilizing conditions. We therefore conclude that the acid state of rhGH consists of a structurally conserved, but dynamically more flexible helical core surrounded by an aura of highly mobile, unstructured loops. However, in spite of its prominent flexibility the acid state of rhGH cannot be considered a "molten globule" state because of its high stability. It appears from our work that under certain conditions, a protein can tolerate a considerable increase in flexibility of its backbone, along with an increased penetration of water into its core, while still maintaining a stable folded conformation.

ST-Segment Analysis Using Wireless Technology in Acute Myocardial Infarction (STAT-MI) trial.

PubMed

Dhruva, Vivek N; Abdelhadi, Samir I; Anis, Ather; Gluckman, William; Hom, David; Dougan, William; Kaluski, Edo; Haider, Bunyad; Klapholz, Marc

2007-08-07

Our goal was to examine the effects of implementing a fully automated wireless network to reduce door-to-intervention times (D2I) in ST-segment elevation myocardial infarction (STEMI). Wireless technologies used to transmit prehospital electrocardiograms (ECGs) have helped to decrease D2I times but have unrealized potential. A fully automated wireless network that facilitates simultaneous 12-lead ECG transmission from emergency medical services (EMS) personnel in the field to the emergency department (ED) and offsite cardiologists via smartphones was developed. The system is composed of preconfigured Bluetooth devices, preprogrammed receiving/transmitting stations, dedicated e-mail servers, and smartphones. The network facilitates direct communication between offsite cardiologists and EMS personnel, allowing for patient triage directly to the cardiac catheterization laboratory from the field. Demographic, laboratory, and time interval data were prospectively collected and compared with calendar year 2005 data. From June to December 2006, 80 ECGs with suspected STEMI were transmitted via the network. Twenty patients with ECGs consistent with STEMI were triaged to the catheterization laboratory. Improvement was seen in mean door-to-cardiologist notification (-14.6 vs. 61.4 min, p < 0.001), door-to-arterial access (47.6 vs. 108.1 min, p < 0.001), time-to-first angiographic injection (52.8 vs. 119.2 min, p < 0.001), and D2I times (80.1 vs. 145.6 min, p < 0.001) compared with 2005 data. A fully automated wireless network that transmits ECGs simultaneously to the ED and offsite cardiologists for the early evaluation and triage of patients with suspected STEMI can decrease D2I times to <90 min and has the potential to be broadly applied in clinical practice.

Exploring the Feasibility of Reputation Models for Improving P2P Routing under Churn

NASA Astrophysics Data System (ADS)

Sànchez-Artigas, Marc; García-López, Pedro; Herrera, Blas

Reputation mechanisms help peer-to-peer (P2P) networks to detect and avoid unreliable or uncooperative peers. Recently, it has been discussed that routing protocols can be improved by conditioning routing decisions to the past behavior of forwarding peers. However, churn — the continuous process of node arrival and departure — may severely hinder the applicability of rating mechanisms. In particular, short lifetimes mean that reputations are often generated from a small number of transactions.

GenCLiP 2.0: a web server for functional clustering of genes and construction of molecular networks based on free terms.

PubMed

Wang, Jia-Hong; Zhao, Ling-Feng; Lin, Pei; Su, Xiao-Rong; Chen, Shi-Jun; Huang, Li-Qiang; Wang, Hua-Feng; Zhang, Hai; Hu, Zhen-Fu; Yao, Kai-Tai; Huang, Zhong-Xi

2014-09-01

Identifying biological functions and molecular networks in a gene list and how the genes may relate to various topics is of considerable value to biomedical researchers. Here, we present a web-based text-mining server, GenCLiP 2.0, which can analyze human genes with enriched keywords and molecular interactions. Compared with other similar tools, GenCLiP 2.0 offers two unique features: (i) analysis of gene functions with free terms (i.e. any terms in the literature) generated by literature mining or provided by the user and (ii) accurate identification and integration of comprehensive molecular interactions from Medline abstracts, to construct molecular networks and subnetworks related to the free terms. http://ci.smu.edu.cn. Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Protecting Data Privacy in Structured P2P Networks

NASA Astrophysics Data System (ADS)

Jawad, Mohamed; Serrano-Alvarado, Patricia; Valduriez, Patrick

P2P systems are increasingly used for efficient, scalable data sharing. Popular applications focus on massive file sharing. However, advanced applications such as online communities (e.g., medical or research communities) need to share private or sensitive data. Currently, in P2P systems, untrusted peers can easily violate data privacy by using data for malicious purposes (e.g., fraudulence, profiling). To prevent such behavior, the well accepted Hippocratic database principle states that data owners should specify the purpose for which their data will be collected. In this paper, we apply such principles as well as reputation techniques to support purpose and trust in structured P2P systems. Hippocratic databases enforce purpose-based privacy while reputation techniques guarantee trust. We propose a P2P data privacy model which combines the Hippocratic principles and the trust notions. We also present the algorithms of PriServ, a DHT-based P2P privacy service which supports this model and prevents data privacy violation. We show, in a performance evaluation, that PriServ introduces a small overhead.

Intelligent system for automatic feature detection and selection or identification

DOEpatents

Sun, C.T.; Shiang, P.S.; Jang, J.S.; Fu, C.Y.

1997-09-02

A neural network uses a fuzzy membership function, the parameters of which are adaptive during the training process, to parameterize the interconnection weights between an (n{minus}1)`th layer and an n`th layer of the network. Each j`th node in each k`th layer of the network except the input layer produces its output value y{sub k,j} according to the function shown in Equation 1 where N{sub k{minus}1} is the number of nodes in layer k{minus}1, i indexes the nodes of layer k{minus}1 and all the w{sub k,i,j} are interconnection weights. The interconnection weights to all nodes j in the n`th layer are given by w{sub n,i,j}=w{sub n,j} (i, p{sub n,j,1}, . . . , p{sub n,j},p{sub n}). The apparatus is trained by setting values for at least one of the parameters p{sub n,j,1}, . . . , p{sub n,j},Pn. Preferably the number of parameters P{sub n} is less than the number of nodes N{sub n{minus}1} in layer n{minus}1. W{sub n,j} (i,p{sub n,j,1}, . . . , p{sub n,j},Pn) can be convex in i, and it can be bell-shaped. Sample functions for w{sub n,j} (i, p{sub n,j,1}, . . . , p{sub n,j},Pn) include Equation 2, shown in the patent. 8 figs.

A self-organizing neural network for the traveling salesman problem that is competitive with simulated annealing.

PubMed

Budinich, M

1996-02-15

Unsupervised learning applied to an unstructured neural network can give approximate solutions to the traveling salesman problem. For 50 cities in the plane this algorithm performs like the elastic net of Durbin and Willshaw (1987) and it improves when increasing the number of cities to get better than simulated annealing for problems with more than 500 cities. In all the tests this algorithm requires a fraction of the time taken by simulated annealing.

Veterans with recent substance use and aggression: PTSD, substance use, and social network behaviors.

PubMed

Sexton, Minden B; Davis, Alan K; Buchholz, Katherine R; Winters, Jamie J; Rauch, Sheila A M; Yzquibell, Maegan; Bonar, Erin E; Friday, Steven; Chermack, Stephen T

2018-04-23

Violence is a salient concern among veterans, yet relationships between psychiatric comorbidity, social networks, and aggression are poorly understood. We examined associations between biopsychosocial factors (substance use, posttraumatic stress disorder [PTSD], and social network behaviors) with aggression. We recruited veterans endorsing past-year aggression and substance use (N = 180) from Department of Veterans Affairs outpatient treatment clinics. Main and interaction effects between probable PTSD, substance use, social network violence and substance use, and veteran violence were examined with negative binomial regressions-specifically, physical aggression toward a relationship partner (PA-P), physical injury of a partner (PI-P), physical aggression toward nonpartners (PA-NP), and physical injury of nonpartners (PI-NP). Alcohol use yielded consistent main effects. PTSD and social network violence demonstrated main effects for PA-NP and PI-NP. PTSD and social network violence interacted to predict PA-P such that social network violence appeared salient only in the context of PTSD. PTSD was associated with PI-P, PA-NP, and PI-NP in social network substance use models. In the PA-P model including social network substance use, veterans with PTSD reported greater PA-P in the context of greater social network substance use, whereas veterans without PTSD endorsed PA-P concurrent with greater alcohol frequency. For PI-P, PTSD interacted with alcohol to predict a greater likelihood of partner injury in the context of social network substance use. Investigated variables demonstrated unique associations within the context of specific relationships and the severity of behaviors. Overall, the findings underscore the importance of biopsychosocial models for understanding veteran violence. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Identification and functional analysis of risk-related microRNAs for the prognosis of patients with bladder urothelial carcinoma.

PubMed

Gao, Ji; Li, Hongyan; Liu, Lei; Song, Lide; Lv, Yanting; Han, Yuping

2017-12-01

The aim of the present study was to investigate risk-related microRNAs (miRs) for bladder urothelial carcinoma (BUC) prognosis. Clinical and microRNA expression data downloaded from the Cancer Genome Atlas were utilized for survival analysis. Risk factor estimation was performed using Cox's proportional regression analysis. A microRNA-regulated target gene network was constructed and presented using Cytoscape. In addition, the Database for Annotation, Visualization and Integrated Discovery was used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment, followed by protein-protein interaction (PPI) network analysis. Finally, the K-clique method was applied to analyze sub-pathways. A total of 16 significant microRNAs, including hsa-miR-3622a and hsa-miR-29a, were identified (P<0.05). Following Cox's proportional regression analysis, hsa-miR-29a was screened as a prognostic marker of BUC risk (P=0.0449). A regulation network of hsa-miR-29a comprising 417 target genes was constructed. These target genes were primarily enriched in GO terms, including collagen fibril organization, extracellular matrix (ECM) organization and pathways, such as focal adhesion (P<0.05). A PPI network including 197 genes and 510 interactions, was constructed. The top 21 genes in the network module were enriched in GO terms, including collagen fibril organization and pathways, such as ECM receptor interaction (P<0.05). Finally, 4 sub-pathways of cysteine and methionine metabolism, including paths 00270_4, 00270_1, 00270_2 and 00270_5, were obtained (P<0.01) and identified to be enriched through DNA (cytosine-5)-methyltransferase ( DNMT)3A, DNMT3B , methionine adenosyltransferase 2α ( MAT2A ) and spermine synthase ( SMS ). The identified microRNAs, particularly hsa-miR-29a and its 4 associated target genes DNMT3A, DNMT3B, MAT2A and SMS , may participate in the prognostic risk mechanism of BUC.

The Contribution of the Division of Radiophysics Murraybank Field Station to International Radio Astronomy

NASA Astrophysics Data System (ADS)

Wendt, Harry; Orchiston, Wayne; Slee, Bruce

During the 1950s Australia was one of the world's foremost astronomical nations owing primarily to the work of the dynamic radio astronomy group within the Commonwealth Scientific and Industrial Research Organisation's Division of Radiophysics. Most of the observations were made at the network of field stations maintained by the Division in or near Sydney, and one of these field stations was Murraybank in the north-western suburbs of Sydney. GVaucouleursDe1954The Magellanic Clouds and the GalaxyThe Observatory7423311954Obs....74...23DDe Vaucouleurs, G., 1954a. The Magellanic Clouds and the Galaxy. The Observatory, 74, 23-31. GVaucouleursDe1954The Magellanic Clouds and the Galaxy, IIThe Observatory741581641954Obs....74..158DDe Vaucouleurs, G., 1954b. The Magellanic Clouds and the Galaxy, II. The Observatory, 74, 158-164. GVaucouleursDe1961Classification and radial velocities of bright southern galaxiesMemoirs of the Royal Astronomical Society6869871961MmRAS..68...69DDe Vaucouleurs, G., 1961. Classification and radial velocities of bright southern galaxies. Memoirs of the Royal Astronomical Society, 68, 69-87. JDeane2006Vacuum Tube SupercomputerSydneyScience Foundation for Physics and the Australian Computer Museum SocietyDeane, J., 2006. Vacuum Tube Supercomputer. Sydney, Science Foundation for Physics and the Australian Computer Museum Society. NHDeiter1965Neutral hydrogen near the galactic polesAstErickson, W.C., Helfer, H.L., and Tatel, H.E., 1959. A survey of neutral hydrogen at high galactic latitudes. In Bracewell, 390-397. MWFeastADThackerayAJWesselink1957Radial velocities of southern B stars determined at the Radcliffe Observatory (Paper II) (summary)Monthly Notices of the Royal Astronomical Society1175791957MNRAS.117..579FFeast, M.W., Thackeray, A.D., and Wesselink, A.J., 1957. Radial velocities of southern B stars determined at the Radcliffe Observatory (Paper II) (summary). Monthly Notices of the Royal Astronomical Society, 117, 579. KCFreeman1970On the disks of spiral and SO galaxiesAstrophysical Journal1608118301970ApJ...160..811F10.1086/150474Freeman, K.C., 1970. On the disks of spiral and SO galaxies. Astrophysical Journal, 160, 811-830. Getmanzev, G.G., Tankevitch, K.S., and Troitzky, V.S., 1957. Detection of the spectral line of deuterium from the centre of the Galaxy on the wave-length of 91.6 cm. In van de Hulst, 90-91. HCGoldwireMGoss1967Microwave radiation of singly charged helium 3 from HII regionsAstrophysical Journal14915221967ApJ...149...15G10.1086/149225Goldwire, H.C., and Goss, M., 1967. Microwave radiation of singly charged helium 3 from HII regions. Astrophysical Journal, 149, 15-22. JLGreenstein1937The effect of absorbing clouds on the general absorption coefficientAnnals of the Astronomical Observatory of Harvard College105359369Greenstein, J.L., 1937. The effect of absorbing clouds on the general absorption coefficient. Annals of the Astronomical Observatory of Harvard College, 105, 359-369. CSGum1956The extent and excitation of the large H II region in Vela-PuppisThe Observatory761501531956Obs....76..150GGum, C.S., 1956. The extent and excitation of the large H II region in Vela-Puppis. The Observatory, 76, 150-153. KGHenize1956Catalogues of Hα-emission stars and nebulae in the Magellanic CloudsAstrophysical Journal Supplement23153441956ApJS....2..315H10.1086/190025Henize, K.G., 1956. Catalogues of Hα-emission stars and nebulae in the Magellanic Clouds. Astrophysical Journal Supplement, 2, 315-344. JVHindman1967A high resolution study of the distribution and motions of neutral hydrogen in the Small Cloud of MagellanAustralian Journal of Physics201471711967AuJPh..20..147H10.1071/PH670147Hindman, J.V., 1967. A high resolution study of the distribution and motions of neutral hydrogen in the Small Cloud of Magellan. Australian Journal of Physics, 20, 147-171. Hindman, J.V., Kerr, F.J., and McGee, R.X., 1963a. A low resolution hydrogen-line survey of the Magellanic system. II. Interpretation of results. Australian Journal of Physics, 16, 570-583. Hindman, J.V., McGee, R.X., Carter, A.W.L., Holmes, E.C.J., and Beard, M., 1963b. A low resolution hydrogen-line survey of the Magellanic system. I. Observations and digital reduction procedures. Australian Journal of Physics, 16, 552-569. Hodge, P.W., 1960. Studies of the Large Magellanic Cloud. I. The red globular clusters. Astrophysical Journal, 131, 351-357. Hodge, P.W., 1961. Studies of the Large Magellanic Cloud. V. The young populous clusters. Astrophysical Journal, 133, 413-419. WEHowardDGWentzelRXMcGee1963On a correlation between the radial velocities of optical and radio interstellar linesAstrophysical Journal13898810011963ApJ...138..988H10.1086/147700Howard, W.E., Wentzel, D.G., and McGee, R.X., 1963. On a correlation between the radial velocities of optical and radio interstellar lines. Astrophysical Journal, 138, 988-1001. HMJohnson1961The structure of the Small Magellanic CloudProceedings of the Astronomical Society of the Pacific7320281961PASP...73...20J10.1086/127613Johnson, H.M., 1961. The structure of the Small Magellanic Cloud. Proceedings of the Astronomical Society of the Pacific, 73, 20-28. KIKellermanWOrchistonBSlee2005Gordon James Stanley and the early development of radio astronomy in Australia and the United StatesPublications of the Astronomical Society of Australia2213232005PASA...22...13K10.1071/AS04008Kellerman, K.I., Orchiston, W., and Slee, B., 2005. Gordon James Stanley and the early development of radio astronomy in Australia and the United States. Publications of the Astronomical Society of Australia, 22, 13-23. Kerr, F.J., 1953. Minutes of the Hydrogen-Line Planning Committee Meeting dated 12 November. National Archives of Australia, Sydney, 972420 - C3830 - A1/3/17 Part 1. Kerr, F.J., 1954. Minutes of the Hydrogen Line Planning Committee Meeting dated 9 June. National Archives of Australia, Sydney, 972420 - C3830 - A1/3/17 Part 2. FJKerr1962Galactic velocity models and the interpretation of 21-cm surveysMonthly Notices of the Royal Astronomical Society1233273451962MNRAS.123..327KKerr, F.J., 1962. Galactic velocity models and the interpretation of 21-cm surveys. Monthly Notices of the Royal Astronomical Society, 123, 327-345. FJKerrJVHindmanBJRobinson1954Observations of the 21 cm line from the Magellanic CloudsAustralian Journal of Physics72973141954AuJPh...7..297K10.1071/PH540297Kerr, F.J., Hindman, J.V., and Robinson, B J., 1954. Observations of the 21 cm line from the Magellanic Clouds. Australian Journal of Physics, 7, 297-314. JVKuilenburg1972A systematic search for high-velocity hydrogen outside the Galactic Plane IIAstronomy and Astrophysics162761972A&A....16..276VKuilenburg, J.V., 1972. A systematic search for high-velocity hydrogen outside the Galactic Plane II. Astronomy and Astrophysics, 16, 276. KKKweeCAMullerGWesterhout1954The rotation of the inner parts of the galactic systemBulletin of the Astronomical Institutes of the Netherlands122112221954BAN....12..211KKwee, K.K., Muller, C.A., and Westerhout, G., 1954. The rotation of the inner parts of the galactic system. Bulletin of the Astronomical Institutes of the Netherlands, 12, 211-222. EMLindsay1958The cluster system of the Small Magellanic CloudMonthly Notices of the Royal Astronomical Society1181721821958MNRAS.118..172LLindsay, E.M., 1958. The cluster system of the Small Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 118, 172-182. EMLindsay1961A new catalogue of emission-line stars and planetary nebulae in the SmaDSMathewsonMNClearyJDMurray1974The Magellanic StreamAstrophysical Journal1902912961974ApJ...190..291M10.1086/152875Mathewson, D.S., Cleary, M.N., and Murray, J.D., 1974. The Magellanic Stream. Astrophysical Journal, 190, 291-296. Mathewson, D.S., Healey, J.R., and Rome, J.M., 1962. A radio survey of the southern Milky Way at a frequency of 1440 Mc/s. II. The continuum emission from the Galactic disk. Australian Journal of Physics, 15, 369-377. DSMathewsonSRWayteVLFordKRuan1987The `high velocity cloud' origin of the Magellanic systemProceedings of the Astronomical Society of Australia719251987PASAu...7...19MMathewson, D.S., Wayte, S.R., Ford, V.L., and Ruan, K., 1987. The `high velocity cloud' origin of the Magellanic system. Proceedings of the Astronomical Society of Australia, 7, 19-25. NMMcClure-GriffithsLStaveley-SmithFJLockmanMRCalabrettaHAFordPMWKalberlaTMurphyHNakanishiDJPisano2008An interaction of a Magellanic leading arm high-velocity cloud with the Milky Way diskAstrophysical Journal673L143L1462008ApJ...673L.143M10.1086/528683McClure-Griffiths, N.M., Staveley-Smith, L., Lockman, F.J., Calabretta, M.R., Ford, H.A., Kalberla, P.M. W., Murphy, T., Nakanishi, H., and Pisano, D.J., 2008. An interaction of a Magellanic leading arm high-velocity cloud with the Milky Way disk. Astrophysical Journal, 673, L143-L146. McCready, L.L., 1954. Letter to J.L. Pawsey, dated 19 August. National Archives of Australia, Sydney, 974347 - C3830 - F1/4/PAW/1. McCready, L.L., 1957. Letter to J.L. Pawsey, dated 28 October. National Archives of Australia, Sydney, 974347 - C3830 - F1/4/PAW/1. RXMcGee1964Large HI clouds in the GalaxyFJKerrThe Galaxy and the Magellanic Clouds. Proceedings of the International Astronomical Union Symposium No. 20 Held in Canberra March 18-28, 1963Australian Academy of Science. PpCanberra126130McGee, R.X., 1964. Large HI clouds in the Galaxy. In Kerr, F.J. (ed.). The Galaxy and the Magellanic Clouds. Proceedings of the International Astronomical Union Symposium No. 20 Held in Canberra March 18-28, 1963. Canberra, Australian Academy of Science. Pp. 126-130. McGee, R.X., and Milton, J.A., 1964. A sky survey of neutral hydrogen at λ 21 cm. III. Gas at higher radial velocities. Australian Journal of Physics, 17, 128-157. RXMcGeeJDMurray1961McGee, R.X., and Murray, J.D., 1961b. A sky survey of neutral hydrogen at λ 21 cm I. The general distribution and motions of the local gas. Australian Journal of Physics, 14, 260-278. McGee, R.X., Murray, J.D., and Milton, J.A., 1963. A sky survey of neutral hydrogen at λ 21 cm. II. The detailed distribution of low velocity gas. Australian Journal of Physics, 16, 136-170. RXMcGeeJDMurrayJLPawsey1961Streaming of interstellar hydrogen in the vicinity of the SunNature1899579591961Natur.189..957M10.1038/189957a0McGee, R.X., Murray, J.D., and Pawsey, J.L., 1961. Streaming of interstellar hydrogen in the vicinity of the Sun. Nature, 189, 957-959. KMMentenMJReidJForbrichABrunthaler2007The distance to the Orion NebulaAstronomy and Astrophysics4745155202007A&A...474..515M10.1051/0004-6361:20078247Menten, K.M., Reid, M.J., Forbrich, J., and Brunthaler, A., 2007. The distance to the Orion Nebula. Astronomy and Astrophysics, 474, 515-520. CAMullerGWesterhout1957A catalogue of 21-cm line profilesBulletin of the Astronomical Institutes of the Netherlands131511951957BAN....13..151MMuller, C.A., and Westerhout, G., 1957. A catalogue of 21-cm line profiles. Bulletin of the Astronomical Institutes of the Netherlands, 13, 151-195. JDMurrayRXMcGee1958A new hydrogen cloud in Pyxis-HydraThe Observatory782422441958Obs....78..242MMurray, J.D., and McGee, R.X., 1958. A new hydrogen cloud in Pyxis-Hydra. The Observatory, 78, 242-244. JDMurrayRXMcGee1959Neutral hydrogen gas in the Taurus-Orion region observed with a multichannel 21 cm line receiverAustralian Journal of Physics121271331959AuJPh..12..127M10.1071/PH590127Murray, J.D., and McGee, R.X., 1959. Neutral hydrogen gas in the Taurus-Orion region observed with a multichannel 21 cm line receiver. Australian Journal of Physics, 12, 127-133. JDMurrayRXMcGee1963A multi-channel hydrogen line (21 cm) receiverProceedings of the Institute of Radio Engineers Australia24191196Murray, J.D., and McGee, R.X., 1963. A multi-channel hydrogen line (21 cm) receiver. Proceedings of the Institute of Radio Engineers Australia, 24, 191-196. AOllongrenHCHulstvan de1957Corrections of 21-cm line profilesBulletin of the Astronomical Institutes of the Netherlands131962001957BAN....13..196OOllongren, A., and van de Hulst, H.C., 1957. Corrections of 21-cm line profiles. Bulletin of the Astronomical Institutes of the Netherlands, 13, 196-200. WOrchiston1993New Zealand's role in the identification of the first "radio stars"Southern Stars3546521993SouSt..35...46OOrchiston, W., 1993. New Zealand's role in the identification of the first "radio stars." Southern Stars, 35, 46-52. WOrchiston1994John Bolton, discrete sources, and the New Zealand field-trip of 1948Australian Journal of Physics475415471994AuJPh..47..541OOrchiston, W., 1994. John Bolton, discrete sources, and the New Zealand field-trip of 1948. Australian Journal of Physics, 47, 541-547 Orchiston, W., 2004. The rise and fall of the Chris Cross: a pioneering Australian radio telescope. In Orchiston, W., Stephenson, R., Debarbat, S., and Nha, I.-S. (eds.). Astronomical Instruments and Archives from the Asia-Pacific Region. Seoul, IAU Commission 41. Pp. 157-162. WOrchistonDMathewson2009Chris Christiansen and the Chris CrossJournal of Astronomical History and Heritage1211322009JAHH...12...11OOrchiston, W., and Mathewson, D., 2009. Chris Christiansen and the Chris Cross. Journal of Astronomical History and Heritage, 12, 11-32. WOrchistonBSlee2002Ingenuity and initiative in Australian radio astronomy: the Dover Heights `hole-in-the-ground' antennaJournal of Astronomical History and Heritage521342002JAHH....5...21OOrchiston, W., and Slee, B., 2002. Ingenuity and initiative in Australian radio astronomy: the Dover Heights `hole-in-the-ground' antenna. Journal of Astronomical History and Heritage, 5, 21-34. WOrchistonBSlee2005The Radiophysics field stations and the early development of radio astronomyWOrchistonThe New Astronomy: Opening the Electromagnetic Window and Expanding our View of Planet EarthSpringer. PpDordrecht11916810.1007/1-4020-3724-4_8Orchiston, W., and Slee, B., 2005. The Radiophysics field stations and the early development of radio astronomy. In Orchiston, W. (ed.). The New Astronomy: Opening the Electromagnetic Window and Expanding our View of Planet Earth. Dordrecht, Springer. Pp. 119-168. WOrchistonTNakamuraRStrom2011Highlighting the History of Astronomy in the Asia-Pacific RegionNew YorkSpringerOrchiston, W., Nakamura, T., and Strom, R. (eds.), 2011. Highlighting the History of Astronomy in the Asia-Pacific Region. New York, Springer. AEERodgersKADudevoirJCCarterBJFanousEKratzenberg2005Deuterium abundance in the interstellar gas of the Galactic Anticentre from the 327 MHz LineAstrophysical Journal630L41L442005ApJ...630L..41R10.1086/466524Rodgers, A.E.E., Dudevoir, K.A., Carter, J.C., Fanous, B.J., and Kratzenberg, E., 2005. Deuterium abundance in the interstellar gas of the Galactic Anticentre from the 327 MHz Line. Astrophysical Journal, 630, L41-L44. VCRubinWKFord1970Rotation of the Andromeda Nebula from a spectroscopic survey of emission regionsAstrophysical Journal1593794031970ApJ...159..379R10.1086/150317Rubin, V.C., and Ford, W.K., 1970. Rotation of the Andromeda Nebula from a spectroscopic survey of emission regions. Astrophysical Journal, 159, 379-403. MSchmidt1957Spiral structure in the inner parts of the galactic system derived from the hydrogen emission at 21-cm wavelengthBulletin of the Astronomical Institutes of the Netherlands132472681957BAN....13..247SSchmidt, M., 1957. Spiral structure in the inner parts of the galactic system derived from the hydrogen emission at 21-cm wavelength. Bulletin of the Astronomical Institutes of the Netherlands, 13, 247-268. GAShain1957The inclination to the Galactic Equator of the general magnetic field of LSSparkeJSGallagher2000Galaxies in the Universe: An IntroductionCambridge University PressCambridgeSparke, L.S., and Gallagher, J.S., 2000. Galaxies in the Universe: An Introduction, Cambridge, Cambridge University Press. SStanimirovicLStaveley-SmithJMDickeyRJSaultSLSnowden1999The large-scale HI structure of the Small Magellanic CloudMonthly Notices of the Royal Astronomical Society3024174361999MNRAS.302..417S10.1046/j.1365-8711.1999.02013.xStanimirovic, S., Staveley-Smith, L., Dickey, J.M., Sault, R.J., and Snowden, S.L., 1999. The large-scale HI structure of the Small Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 302, 417-436. GJStanleyRPrice1956An investigation of monochromatic radio emission of deuterium from the GalaxyNature177122112221956Natur.177.1221S10.1038/1771221a0Stanley, G.J., and Price, R., 1956. An investigation of monochromatic radio emission of deuterium from the Galaxy. Nature, 177, 1221-1222. Stanley, G.J., 1994. Recollections of John G. Bolton at Dover Heights and Caltech. Australian Journal of Physics, 47, 507-516. WTSullivan2009Cosmic Noise. A History of Early Radio AstronomyCambridge University PressCambridgeSullivan, W.T., 2009. Cosmic Noise. A History of Early Radio Astronomy. Cambridge, Cambridge University Press. Townes, C.H., 1957. Microwave and radio-frequency resonance lines of interest to radio astronomy. In van de Hulst, 92-103. HCHulstvan de1957Radio Astronomy, Proceedings from 4th IAU Symposium. International Astronomical UnionCambridgeCambridge University Pressvan de Hulst, H.C. (ed.), 1957. Radio Astronomy, Proceedings from 4th IAU Symposium. International Astronomical Union. Cambridge, Cambridge University Press. HCHulstvan de1958Density and velocity distribution of the interstellar gasReviews of Modern Physics309139231958RvMP...30..913V10.1103/RevModPhys.30.913van de Hulst, H.C., 1958. Density and velocity distribution of the interstellar gas. Reviews of Modern Physics, 30, 913-923. HCHulstvan deCAMullerJHOort1954The spiral structure of the outer part of the galactic system derived from the hydrogen emission at 21 cm wavelengthBulletin of the Astronomical Institutes of the Netherlands121171491954BAN....12..117Vvan de Hulst, H.C., Muller, C.A., and Oort, J.H., 1954. The spiral structure of the outer part of the galactic system derived from the hydrogen emission at 21 cm wavelength. Bulletin of the Astronomical Institutes of the Netherlands, 12, 117-149. HWoerdenvanRStrom2006The beginnings of radio astronomy in the NetherlandsJournal of Astronomical History and Heritage93202006JAHH....9....3Vvan Woerden, H., and Strom, R., 2006. The beginnings of radio astronomy in the Netherlands. Journal of Astronomical History and Heritage, 9, 3-20. PWannierGTWrixon1972An unusual high-velocity hydrogen featureAstrophysical Journal1731191231972ApJ...173L.119W10.1086/180930Wannier, P., and Wrixon, G.T., 1972. An unusual high-velocity hydrogen feature. Astrophysical Journal, 173, 119-123. Wendt, H.W., 2008. The Contribution of the CSIRO Division of Radiophysics Potts Hill and Murraybank Field Stations to International Radio Astronomy. Ph.D. Thesis, Centre for Astronomy, James Cook University, Townsville, Australia. Wendt, H., Orchiston, W., and Slee, B., 2008. W.N. Christiansen and the initial Australian investigation of the 21cm hydrogen line. Journal of Astronomical History and Heritage, 11, 185-193. Wendt, H.W., Orchiston, W., and Slee, W., 2011a. The contribution of the Division of Radiophysics Potts Hill field station to international radio astronomy. In Orchiston et al., 379-431. Wendt, H., Orchiston, W., and Slee, B., 2011b. The contribution of W.N. Christiansen to radio astronomy: 1948-1960. In Orchiston et al., 547-587. GWesterhout1957The distribution of atomic hydrogen in the outer parts of the galactic systemBulletin of the Astronomical Institutes of the Netherlands132012461957BAN....13..201WWesterhout, G., 1957. The distribution of atomic hydrogen in the outer parts of the galactic system. Bulletin of the Astronomical Institutes of the Netherlands, 13, 201-246. GWesterhout1958A survey of the continuous radiation from the galactic system at a frequency of 1390 Mc/sBulletin of the Astronomical Institutes of the Netherlands142152601958BAN....14..215WWesterhout, G., 1958. A survey of the continuous radiation from the galactic system at a frequency of 1390 Mc/s. Bulletin of the Astronomical Institutes of the Netherlands, 14, 215-260. JPWild1952The radio-frequency line spectrum of atomic hydrogen and its applications in astronomyAstrophysical Journal1152062211952ApJ...115..206W10.1086/145533Wild, J.P., 1952. The radio-frequency line spectrum of atomic hydrogen and its applications in astronomy. Astrophysical Journal, 115, 206-221.

Synthesis and Crystal Structure of a New Ruthenium Silicophosphate: RuP 3SiO 11

NASA Astrophysics Data System (ADS)

Fukuoka, Hiroshi; Imoto, Hideo; Saito, Taro

1996-01-01

A new ruthenium silicophosphate RuP3SiO11was obtained and the structure was determined by single-crystal X-ray diffraction. It crystallizes in the trigonal space groupR3cwitha= 8.253(3)Å,c= 39.317(4)Å,V= 2319(2)Å3,Z= 12,R= 0.029, andRW= 0.026. The structure is composed of RuO6, Si2O7, and P2O7units. The Si2O7unit shares the six oxygen atoms with six P2O7units, while the P2O7unit shares the six oxygen atoms with two Si2O7units and four RuO6octahedra. The anionic part forms an infinite three-dimensional network of silicophosphate. RuP3SiO11is isotypic with MoP3SiO11.

Adolescents' social environment and depression: social networks, extracurricular activity, and family relationship influences.

PubMed

Mason, Michael J; Schmidt, Christopher; Abraham, Anisha; Walker, Leslie; Tercyak, Kenneth

2009-12-01

The present study examined components of adolescents' social environment (social network, extracurricular activities, and family relationships) in association with depression. A total of 332 adolescents presenting for a routine medical check-up were self-assessed for social network risk (i.e., smoking habits of best male and female friends), extracurricular activity level (i.e., participation in organized sports teams, clubs, etc.), family relationship quality (i.e., cohesion and conflict), and symptoms of depression (i.e., minimal, mild, moderate/severe). Results of a forward linear regression modeling indicate that social environment components were associated with a significant proportion of the variance in adolescent depression (Adjusted R (2) = .177, p < or = .05). Specifically, adolescent females (beta = .166, p < .01) and those having more smokers in their social network (beta = .107, p < .05) presented with significantly greater depression symptoms. Conversely, adolescents who engaged in more extracurricular activities (beta = -.118, p < .05) and experienced higher quality family relationships (beta = -.368, p < .001) presented with significantly lower depressive symptoms. These findings highlight the important role that the social environment plays in adolescent depression, as well as yields new insights into socially-based intervention targets that may ameliorate adolescent depression. These intervention targets may be gender-specific, include positive social network skills training, increase adolescents' engagement in organized activities, and attend to the quality of their family relationships.

Selected Bibliography and Index to Publications about ARPANET

DTIC Science & Technology

1976-02-15

TABLE OF CONTENTS Preface Selected ARPANET Bibliography Subject and Document Number Index A4, .i. ! 1! II 1 1 2l i , * - :--. ’. __ _ __ _ __ _ _ t...34 Information processing 74. Proceedings of the IFIP Con- gress 74. 5. Systems for management and administration, 1974, p. 1052 - 1056. Analysis and optimization...perfonnance. Glen Cove, N. Y.,: Network Analysis Corporation, Apr 73. 148 p. 039 ARIPANET directory. Menlo Park, Ca., ARPA Network Information Center

Federated Ground Station Network Model and Interface Specification

DTIC Science & Technology

2014-12-01

interface definition language JSON JavaScript Object Notation LEO low Earth orbit LNA low-noise amplifier MC3 Mobile CubeSat Command and Control...Naval Research Laboratory OQPSK offset quadrature phase-shift keying xviii P2P peer-to-peer PKI public key infrastructure REST Representational...enhanced our work being performed on the Mobile CubeSat Command and Control (MC3) ground station network. You also provided crucial guidance from

Neuron-Inspired Interpenetrative Network Composed of Cobalt-Phosphorus-Derived Nanoparticles Embedded within Porous Carbon Nanotubes for Efficient Hydrogen Production.

PubMed

Shen, Juanxia; Yang, Zhi; Ge, Mengzhan; Li, Ping; Nie, Huagui; Cai, Qiran; Gu, Cancan; Yang, Keqin; Huang, Shaoming

2016-07-13

The ongoing search for cheap and efficient hydrogen evolution reaction (HER) electrocatalysts to replace currently used catalysts based on Pt or its alloys has been considered as an prevalent strategy to produce renewable and clean hydrogen energy. Herein, inspired by the neuron structure in biological systems, we demonstrate a novel fabrication strategy via a simple two-step method for the synthesis of a neuronlike interpenetrative nanocomposite network of Co-P embedded in porous carbon nanotubes (NIN-Co-P/PCNTs). It is found that the interpenetrative network provides a natural transport path to accelerate the hydrogen production process. The embedded-type structure improves the utilization ratio of Co-P and the hollow, tubelike, and porous structure of PCNTs further promote charge and reactant transport. These factors allow the as-prepared NIN-Co-P/PCNTs to achieve a onset potential low to 43 mV, a Tafel slope as small as 40 mV/decade, an excellent stability, and a high turnover frequency value of 3.2 s(-1) at η = 0.2 V in acidic conditions. These encouraging properties derived from the neuronlike interpenetrative network structure might offer new inspiration for the preparation of more nanocomposites for applications in other catalytic and optoelectronic field.

An incremental community detection method for social tagging systems using locality-sensitive hashing.

PubMed

Wu, Zhenyu; Zou, Ming

2014-10-01

An increasing number of users interact, collaborate, and share information through social networks. Unprecedented growth in social networks is generating a significant amount of unstructured social data. From such data, distilling communities where users have common interests and tracking variations of users' interests over time are important research tracks in fields such as opinion mining, trend prediction, and personalized services. However, these tasks are extremely difficult considering the highly dynamic characteristics of the data. Existing community detection methods are time consuming, making it difficult to process data in real time. In this paper, dynamic unstructured data is modeled as a stream. Tag assignments stream clustering (TASC), an incremental scalable community detection method, is proposed based on locality-sensitive hashing. Both tags and latent interactions among users are incorporated in the method. In our experiments, the social dynamic behaviors of users are first analyzed. The proposed TASC method is then compared with state-of-the-art clustering methods such as StreamKmeans and incremental k-clique; results indicate that TASC can detect communities more efficiently and effectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Early childhood behavioral inhibition, adult psychopathology and the buffering effects of adolescent social networks: a twenty-year prospective study.

PubMed

Frenkel, Tahl I; Fox, Nathan A; Pine, Daniel S; Walker, Olga L; Degnan, Kathryn A; Chronis-Tuscano, Andrea

2015-10-01

We examined whether the temperament of behavioral inhibition is a significant marker for psychopathology in early adulthood and whether such risk is buffered by peer social networks. Participants (N = 165) were from a prospective study spanning the first two decades of life. Temperament was characterized during infancy and early childhood. Extent of involvement in peer social networks was measured during adolescence, and psychopathology was assessed in early adulthood. Latent Class Analyses generated comprehensive variables at each of three study time-points. Regressions assessed (a) the direct effect of early behavioral inhibition on adult psychopathology (b) the moderating effect of adolescent involvement in social peer networks on the link between temperamental risk and adult psychopathology. Stable behavioral inhibition in early childhood was negatively associated with adult mental health (R(2 ) = .07, p = .005, β = -.26), specifically increasing risk for adult anxiety disorders (R(2) = .04, p = .037, β = .19). These temperament-pathology relations were significantly moderated by adolescent peer group social involvement and network size (Total R(2) = .13, p = .027, β = -.22). Temperament predicted heightened risk for adult anxiety when adolescent social involvement was low (p = .002, β = .43), but not when adolescent social involvement was high. Stable behavioral inhibition throughout early childhood is a risk factor for adult anxiety disorders and interacts with adolescent social involvement to moderate risk. This is the first study to demonstrate the critical role of adolescent involvement in socially active networks in moderating long-lasting temperamental risk over the course of two decades, thus informing prevention/intervention approaches. © 2015 Association for Child and Adolescent Mental Health.

Sexual Behavior and Network Characteristics and Their Association with Bacterial Sexually Transmitted Infections among Black Men Who Have Sex with Men in the United States.

PubMed

Scott, Hyman M; Irvin, Risha; Wilton, Leo; Van Tieu, Hong; Watson, Chauncey; Magnus, Manya; Chen, Iris; Gaydos, Charlotte; Hussen, Sophia A; Mannheimer, Sharon; Mayer, Kenneth; Hessol, Nancy A; Buchbinder, Susan

2015-01-01

Black men who have sex with men (MSM) have a high prevalence of bacterial sexually transmitted infections (STIs), and individual risk behavior does not fully explain the higher prevalence when compared with other MSM. Using the social-ecological framework, we evaluated individual, social and sexual network, and structural factors and their association with prevalent STIs among Black MSM. The HIV Prevention Trials Network 061 was a multi-site cohort study designed to determine the feasibility and acceptability of a multi-component intervention for Black MSM in six US cities. Baseline assessments included demographics, risk behavior, and social and sexual network questions collected information about the size, nature and connectedness of their sexual network. Logistic regression was used to estimate the odds of having any prevalent sexually transmitted infection (gonorrhea, chlamydia, or syphilis). A total of 1,553 Black MSM were enrolled in this study. In multivariate analysis, older age (aOR = 0.57; 95% CI 0.49-0.66, p<0.001) was associated with a lower odds of having a prevalent STI. Compared with reporting one male sexual partner, having 2-3 partners (aOR = 1.74; 95% CI 1.08-2.81, p<0.024) or more than 4 partners (aOR = 2.29; 95% CI 1.43-3.66, p<0.001) was associated with prevalent STIs. Having both Black and non-Black sexual partners (aOR = 0.67; 95% CI 0.45-0.99, p = 0.042) was the only sexual network factor associated with prevalent STIs. Age and the number and racial composition of sexual partners were associated with prevalent STIs among Black MSM, while other sexual network factors were not. Further studies are needed to evaluate the effects of the individual, network, and structural factors on prevalent STIs among Black MSM to inform combination interventions to reduce STIs among these men.

Sexual Behavior and Network Characteristics and Their Association with Bacterial Sexually Transmitted Infections among Black Men Who Have Sex with Men in the United States

PubMed Central

Scott, Hyman M.; Irvin, Risha; Wilton, Leo; Van Tieu, Hong; Watson, Chauncey; Magnus, Manya; Chen, Iris; Gaydos, Charlotte; Hussen, Sophia A.; Mannheimer, Sharon; Mayer, Kenneth; Hessol, Nancy A.; Buchbinder, Susan

2015-01-01

Background Black men who have sex with men (MSM) have a high prevalence of bacterial sexually transmitted infections (STIs), and individual risk behavior does not fully explain the higher prevalence when compared with other MSM. Using the social-ecological framework, we evaluated individual, social and sexual network, and structural factors and their association with prevalent STIs among Black MSM. Methods The HIV Prevention Trials Network 061 was a multi-site cohort study designed to determine the feasibility and acceptability of a multi-component intervention for Black MSM in six US cities. Baseline assessments included demographics, risk behavior, and social and sexual network questions collected information about the size, nature and connectedness of their sexual network. Logistic regression was used to estimate the odds of having any prevalent sexually transmitted infection (gonorrhea, chlamydia, or syphilis). Results A total of 1,553 Black MSM were enrolled in this study. In multivariate analysis, older age (aOR = 0.57; 95% CI 0.49–0.66, p<0.001) was associated with a lower odds of having a prevalent STI. Compared with reporting one male sexual partner, having 2–3 partners (aOR = 1.74; 95% CI 1.08–2.81, p<0.024) or more than 4 partners (aOR = 2.29; 95% CI 1.43–3.66, p<0.001) was associated with prevalent STIs. Having both Black and non-Black sexual partners (aOR = 0.67; 95% CI 0.45–0.99, p = 0.042) was the only sexual network factor associated with prevalent STIs. Conclusions Age and the number and racial composition of sexual partners were associated with prevalent STIs among Black MSM, while other sexual network factors were not. Further studies are needed to evaluate the effects of the individual, network, and structural factors on prevalent STIs among Black MSM to inform combination interventions to reduce STIs among these men. PMID:26720332

Effect of insertion torque on titanium implant osseointegration: an animal experimental study.

PubMed

Duyck, Joke; Roesems, Rutger; Cardoso, Marcio V; Ogawa, Toru; De Villa Camargos, Germana; Vandamme, Katleen

2015-02-01

To evaluate the effect of implant insertion torque on the peri-implant bone healing and implant osseointegration. Bilaterally in the tibia of five adult New Zealand white rabbits, 20 implants were installed, subdivided into four groups, corresponding to two insertion torque conditions (low, < 10 Ncm vs. high > 50 Ncm) and 2 experimental periods (2 weeks vs. 4 weeks of healing). The implant insertion torque was determined by the surgical drill diameter relative to the implant diameter. Implant osseointegration was evaluated by quantitative histology (bone-to-implant contact with host bone [BIC-host], with neoformed bone [BIC-de novo], with both bone types [BIC-total], and peri-implant bone [BA/TA]). Every response was modelled over time using GEE (general estimation equation) with an unstructured variance-covariance matrix to correct for dependency between the measurements from one animal. The statistical significance level of α = 0.05 was applied. Significantly, more BIC-host and BIC-total were recorded for H implants compared with L implants after 2 week of healing (P = 0.010 and P = 0.0001, respectively). However, this result was no longer found for the extended healing period. Furthermore, BIC-total significantly increased over time for L implants (P < 0.00001). In contrast, the significant increase in BA/TA over time was found for H implants (P < 0.01). Finally, H insertion torque led to an increased BA/TA after 4 week of healing (P < 0.02) compared with the L insertion protocol. L insertion torque implants installed in the rabbit tibial bone osseointegrate with considerable de novo bone formation. This bone neoformation enables L implants to catch up, already during the early osseointegration stage, the initial inferior amount BIC contact compared with that of H implants. A negative impact of the created strain environment accompanying H insertion torque implant installation on the biological process of osseointegration could not be observed, at least not at tissue level. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Gender differences associated with orienting attentional networks in healthy subjects.

PubMed

Liu, Gang; Hu, Pan-Pan; Fan, Jin; Wang, Kai

2013-06-01

Selective attention is considered one of the main components of cognitive functioning. A number of studies have demonstrated gender differences in cognition. This study aimed to investigate the gender differences in selective attention in healthy subjects. The present experiment examined the gender differences associated with the efficiency of three attentional networks: alerting, orienting, and executive control attention in 73 healthy subjects (38 males). All participants performed a modified version of the Attention Network Test (ANT). Females had higher orienting scores than males (t = 2.172, P < 0.05). Specifically, females were faster at covert orienting of attention to a spatially cued location. There were no gender differences between males and females in alerting (t = 0.813, P > 0.05) and executive control (t = 0.945, P > 0.05) attention networks. There was a significant gender difference between males and females associated with the orienting network. Enhanced orienting attention in females may function to motivate females to direct their attention to a spatially cued location.

Assessment of Cancer Education Seminars for Appalachian Populations

PubMed Central

Pennell, Michael L.; Dignan, Mark B.; Paskett, Electra D.

2013-01-01

Cancer education seminars for Appalachian populations were conducted to: (1) increase knowledge of existing cancer disparities, (2) disseminate findings from Appalachian community-based participatory research (CBPR) projects, and (3) foster CBPR capacity building among community members by promoting social networking. Evaluation of the seminars was completed by: (1) using pre–post-surveys to assess changes in knowledge and attitudes at three regional and one national seminar and (2) measuring a change in the social network patterns of participants at a national seminar by analyzing the names of individuals known at the beginning and at the end of the seminar by each participant. Among participants, there was a significant increase in knowledge of Appalachian cancer disparities at two seminars [national, t(145)=3.41, p=0.001; Pennsylvania, t(189)=3.00, p=0.003] and a change in attitudes about Appalachia at one seminar [Ohio t(193)=−2.80, p=0.006]. Social network analysis, operationally defined for this study as familiarity with individuals attending the conference, showed participation in the national seminar fostered capacity building for future CBPR by the development of new network ties. Findings indicate that short-term outcomes of the seminars were accomplished. Future educational seminars should consider using social network analysis as a new evaluation methodology. PMID:22131064

P2P Technology for High-Performance Computing: An Overview

NASA Technical Reports Server (NTRS)

Follen, Gregory J. (Technical Monitor); Berry, Jason

2003-01-01

The transition from cluster computing to peer-to-peer (P2P) high-performance computing has recently attracted the attention of the computer science community. It has been recognized that existing local networks and dedicated clusters of headless workstations can serve as inexpensive yet powerful virtual supercomputers. It has also been recognized that the vast number of lower-end computers connected to the Internet stay idle for as long as 90% of the time. The growing speed of Internet connections and the high availability of free CPU time encourage exploration of the possibility to use the whole Internet rather than local clusters as massively parallel yet almost freely available P2P supercomputer. As a part of a larger project on P2P high-performance computing, it has been my goal to compile an overview of the 2P2 paradigm. I have studied various P2P platforms and I have compiled systematic brief descriptions of their most important characteristics. I have also experimented and obtained hands-on experience with selected P2P platforms focusing on those that seem promising with respect to P2P high-performance computing. I have also compiled relevant literature and web references. I have prepared a draft technical report and I have summarized my findings in a poster paper.

An accurate discontinuous Galerkin method for solving point-source Eikonal equation in 2-D heterogeneous anisotropic media

NASA Astrophysics Data System (ADS)

Le Bouteiller, P.; Benjemaa, M.; Métivier, L.; Virieux, J.

2018-03-01

Accurate numerical computation of wave traveltimes in heterogeneous media is of major interest for a large range of applications in seismics, such as phase identification, data windowing, traveltime tomography and seismic imaging. A high level of precision is needed for traveltimes and their derivatives in applications which require quantities such as amplitude or take-off angle. Even more challenging is the anisotropic case, where the general Eikonal equation is a quartic in the derivatives of traveltimes. Despite their efficiency on Cartesian meshes, finite-difference solvers are inappropriate when dealing with unstructured meshes and irregular topographies. Moreover, reaching high orders of accuracy generally requires wide stencils and high additional computational load. To go beyond these limitations, we propose a discontinuous-finite-element-based strategy which has the following advantages: (1) the Hamiltonian formalism is general enough for handling the full anisotropic Eikonal equations; (2) the scheme is suitable for any desired high-order formulation or mixing of orders (p-adaptivity); (3) the solver is explicit whatever Hamiltonian is used (no need to find the roots of the quartic); (4) the use of unstructured meshes provides the flexibility for handling complex boundary geometries such as topographies (h-adaptivity) and radiation boundary conditions for mimicking an infinite medium. The point-source factorization principles are extended to this discontinuous Galerkin formulation. Extensive tests in smooth analytical media demonstrate the high accuracy of the method. Simulations in strongly heterogeneous media illustrate the solver robustness to realistic Earth-sciences-oriented applications.

Nickel-based xerogel catalysts: Synthesis via fast sol-gel method and application in catalytic hydrogenation of p-nitrophenol to p-aminophenol

NASA Astrophysics Data System (ADS)

Feng, Jin; Wang, Qiang; Fan, Dongliang; Ma, Lirong; Jiang, Deli; Xie, Jimin; Zhu, Jianjun

2016-09-01

In order to investigate the roles of three-dimensional network structure and calcium on Ni catalysts, the Ni, Ni-Al2O3, Ni-Ca-Al2O3 xerogel catalysts were successfully synthesized via the fast sol-gel process and chemical reduction method. The crystal structure of three different catalysts was observed with X-ray powder diffraction (XRD). Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption-desorption were employed to investigate the role of network structure of xerogel catalysts and the size distribution of Ni nanoparticles. The catalyst composition was determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) measurement and energy-dispersive X-ray spectroscopy (EDS). Temperature-programmed reduction (TPR) experiments were carried out to investigate the reducibility of nickel species and the interaction between nickel species and alumina. The catalytic hydrogenation of p-nitrophenol to p-aminophenol was investigated over the prepared nickel-based xerogel catalysts. The conversion of p-nitrophenol was monitored by UV spectrophotometry and high performance liquid chromatography (HPLC). The results show that the catalysts are highly selective for the conversion of p-nitrophenol to p-aminophenol and the order of catalytic activities of the catalysts is Ni < Ni-Al2O3 < Ni-Ca-Al2O3. The catalysts were recycled and were used to evaluate the reutilization.

Distributed Peer-to-Peer Target Tracking in Wireless Sensor Networks

PubMed Central

Wang, Xue; Wang, Sheng; Bi, Dao-Wei; Ma, Jun-Jie

2007-01-01

Target tracking is usually a challenging application for wireless sensor networks (WSNs) because it is always computation-intensive and requires real-time processing. This paper proposes a practical target tracking system based on the auto regressive moving average (ARMA) model in a distributed peer-to-peer (P2P) signal processing framework. In the proposed framework, wireless sensor nodes act as peers that perform target detection, feature extraction, classification and tracking, whereas target localization requires the collaboration between wireless sensor nodes for improving the accuracy and robustness. For carrying out target tracking under the constraints imposed by the limited capabilities of the wireless sensor nodes, some practically feasible algorithms, such as the ARMA model and the 2-D integer lifting wavelet transform, are adopted in single wireless sensor nodes due to their outstanding performance and light computational burden. Furthermore, a progressive multi-view localization algorithm is proposed in distributed P2P signal processing framework considering the tradeoff between the accuracy and energy consumption. Finally, a real world target tracking experiment is illustrated. Results from experimental implementations have demonstrated that the proposed target tracking system based on a distributed P2P signal processing framework can make efficient use of scarce energy and communication resources and achieve target tracking successfully.

EMPHASIS™/Nevada UTDEM User Guide Version 2.1.2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, C. David; Pasik, Michael F.; Seidel, David B.

The Unstructured Time-Domain ElectroMagnetics (UTDEM) portion of the EMPHASIS suite solves Maxwell’s equations using finite-element techniques on unstructured meshes. This document provides user-specific information to facilitate the use of the code for applications of interest.

Structural Change and Interaction Behavior in Multimodal Networks

DTIC Science & Technology

2010-07-30

S̃q~v = PD( ∑ p Sq→p)− 1 2~v, so λ and D( ∑ p Sq→p) − 1 2~v are an eigenvalue-eigenvector pair for P. By the Perron - Frobenius theorem, we know that λ... Frobenius norm, and α = 11+γ . The closed form solution is F ∗ p→q = (1 − α)(Inq − αS̃q)−1ATp→q [30, 26]. 4 Experiment We evaluated our method for...of mode Xp and the jth cluster of Xq. An approximate factorization is then achieved by minimizing a loss function comprised of the Frobenius norms of

Structural analysis of cortical porosity applied to HR-pQCT data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tjong, Willy, E-mail: wwtjong@gmail.com; Nirody, Jasmine, E-mail: jnirody@berkeley.edu; Burghardt, Andrew J., E-mail: andrew.burghardt@ucsf.edu

2014-01-15

Purpose: The investigation of cortical porosity is an important aspect of understanding biological, pathoetiological, and biomechanical processes occurring within the skeleton. With the emergence of HR-pQCT as a noninvasive tool suitable for clinical use, cortical porosity at appendicular sites can be directly visualizedin vivo. The aim of this study was to introduce a novel topological analysis of the cortical pore network for HR-pQCT data and determine the influence of resolution on measures of cortical pore network microstructure and topology. Methods: Cadaveric radii were scanned using HR-pQCT at two different voxel sizes (41 and 82μm) and also using μCT at amore » voxel size of 18 μm. HR-pQCT and μCT image sets were spatially coregistered. Segmentation and quantification of cortical porosity (Ct.Po) and mean pore diameter (Ct.Po.Dm) were achieved using an established extended cortical analysis technique. Topological classification of individual pores was performed using topology-preserving skeletonization and multicolor dilation algorithms. Based on the pore skeleton topological classification, the following parameters were quantified: total number of planar surface-skeleton canals (N.Slabs), tubular curve-skeleton canals (N.Tubes), and junction elements (N.Junctions), mean slab volume (Slab.Vol), mean tube volume (Tube.Vol), mean slab orientation (Slab.θ), mean tube orientation (Tube.θ), N.Slabs/N.Tubes, and integral (total) slab volume/integral tube volume (iSlab.Vol/iTube.Vol). An in vivo reproducibility study was also conducted to assess short-term precision of the topology parameters. Precision error was characterized using root mean square coefficient of variation (RMSCV%). Results: Correlations toμCT values for Ct.Po were significant for both the 41 and 82 μm HR-pQCT data (41: r{sup 2} = 0.82, p < 0.001, 82: r{sup 2} = 0.75, p < 0.001). For Ct.Po.Dm, only the 41 μm data were significantly predictive of μCT values (r{sup 2} = 0.72, p < 0.01) Data at both HR-pQCT voxel sizes were strongly predictive of the μCT values for N.Slabs (41: r{sup 2} = 0.93, p < 0.001; 82: r{sup 2} = 0.84, p < 0.001), N.Tubes (41: r{sup 2} = 0.94, p < 0.001; 82: r{sup 2} = 0.84, p < 0.001), and N.Junctions (41: r{sup 2} = 0.93, p < 0.001; 82: r{sup 2} = 0.78, p < 0.001), though proportional bias was evident in these correlations. Weak correlations were seen for iSlab.Vol/iTube.Vol at both voxel sizes (41: r{sup 2} = 0.52, p < 0.01; 82: r{sup 2} = 0.39, p < 0.05). Slab.Vol was significantly correlated to μCT data at 41 μm (r{sup 2} = 0.60, p < 0.01) but not at 82 μm, while Tube.Vol was significantly correlated at both voxel sizes (41: r{sup 2} = 0.79, p < 0.001; 82: r{sup 2} = 0.68, p < 0.01). In vivo precision error for these parameters ranged from 2.31 to 9.68 RMSCV%. Conclusions: Strong correlations betweenμCT- and HR-pQCT-derived measurements were found, particularly in HR-pQCT images obtained at 41 μm. These data are in agreement with our previous study investigating the effect of voxel size on standard HR-pQCT metrics of trabecular and cortical microstructure, and extend our previous findings to include topological descriptors of the cortical pore network.« less

Effects of third trimester-equivalent ethanol exposure on Cl(-) co-transporter expression, network activity, and GABAergic transmission in the CA3 hippocampal region of neonatal rats.

PubMed

Everett, Julie C; Licón-Muñoz, Yamhilette; Valenzuela, C Fernando

2012-09-01

Fetal alcohol spectrum disorders are often associated with structural and functional hippocampal abnormalities, leading to long-lasting learning and memory deficits. The mechanisms underlying these abnormalities are not fully understood. Here, we investigated whether ethanol exposure during the 3rd trimester-equivalent period alters spontaneous network activity that is involved in neuronal circuit development in the CA3 hippocampal region. This activity is driven by GABA(A) receptors, which can have excitatory actions in developing neurons as a consequence of greater expression of the Cl(-) importer, NKCC1, with respect to expression of the Cl(-) exporter, KCC2, resulting in high [Cl(-)](i). Rat pups were exposed to ethanol vapor from postnatal day (P) 2-16 (4 h/day). Weight gain was significantly reduced in pups exposed to ethanol compared to control at P15 and 16. Brain slices were prepared immediately after the end of the 4-h exposure on P4-16 and experiments were also performed under ethanol-free conditions at the end of the exposure paradigm (P17-22). Ethanol exposure did not significantly affect expression of KCC2 or NKCC1, nor did it affect network activity in the CA3 hippocampal region. Ethanol exposure significantly decreased the frequency (at P9-11) and increased the amplitude (at P5-8 and P17-21) of GABA(A) receptor-mediated miniature postsynaptic currents. These data suggest that repeated in vivo exposure to ethanol during the 3rd trimester-equivalent period alters GABAergic transmission in the CA3 hippocampal region, an effect that could lead to abnormal circuit maturation and perhaps contribute to the pathophysiology of fetal alcohol spectrum disorders. Copyright © 2012 Elsevier Inc. All rights reserved.

RNA sequencing reveals significant miRNAs in Atypical endometrial hyperplasia.

PubMed

Tang, Shiqian; Dai, Yinmei

2018-06-01

In this paper, we aimed to investigate the miRNAs that played a regulatory role in the development of atypical endometrial hyperplasia (AEH). RNA sequencing was performed for endometrial tissues from 3 AEH patients and 3 endometrial normal hyperplasia patients. RNA sequencing data were processed and differentially expressed (DE) miRNAs were identified between AEH and controls. The target genes for DE miRNAs were identified and mapped to the protein-protein interaction (PPI) network. The miRNA related functions were predicted and miRNA-disease gene network was constructed. Total 18 DE miRNAs were overlapped in three sample groups, among which hsa-miR-577, hsa-miR-182-5p and hsa-miR-183-5p were top three miRNAs that targeting largest number of genes. Function analysis showed that the 18 overlapped miRNAs mainly related with cancer and signaling transduction related pathways. PPI network showed that total 12 genes were among top 20 genes based on three network topological features including BCL2, UMPS, MAPK13, PRKCB, CREB1, IGF1, SP1, SMAD3, IGF1R, NOTCH2, WNT5A, TK2. Top 10 miRNAs in miRNA-disease gene network were identified such as hsa-miR-577 (degree = 17), hsa-miR-182-5p (degree = 16) and hsa-miR-3609 (degree = 13). hsa-miR-577 and hsa-miR-182-5p may play regulatory role in AEH through AMPK signal pathway and Wnt signaling pathway. Copyright © 2018 Elsevier B.V. All rights reserved.

People-to-People Lending: The Emerging E-Commerce Transformation of a Financial Market

NASA Astrophysics Data System (ADS)

Wang, Hui; Greiner, Martina; Aronson, Jay E.

This paper provides an overview of the concept of people-to-people (P2P) lending, a relatively new e-commerce phenomenon that has the potential to radically change the structure of the loan segment of the financial industry. P2P lending creates a marketplace of individuals and a social fabric through which these individuals interact. It provides efficient information transfer, thus perhaps creating more perfect markets. P2P lending requires information systems support to make it function, and to provide a social network mechanism that may be crucial for its success. We discuss different P2P lending marketplace models, and how information systems support the creation and management of these new marketplaces, and how they support the individuals involved. We conclude by providing some important research questions and directions, and issues for which further investigation is called.

In vivo intracellular pH measurements in tobacco and Arabidopsis reveal an unexpected pH gradient in the endomembrane system.

PubMed

Martinière, Alexandre; Bassil, Elias; Jublanc, Elodie; Alcon, Carine; Reguera, Maria; Sentenac, Hervé; Blumwald, Eduardo; Paris, Nadine

2013-10-01

The pH homeostasis of endomembranes is essential for cellular functions. In order to provide direct pH measurements in the endomembrane system lumen, we targeted genetically encoded ratiometric pH sensors to the cytosol, the endoplasmic reticulum, and the trans-Golgi, or the compartments labeled by the vacuolar sorting receptor (VSR), which includes the trans-Golgi network and prevacuoles. Using noninvasive live-cell imaging to measure pH, we show that a gradual acidification from the endoplasmic reticulum to the lytic vacuole exists, in both tobacco (Nicotiana tabacum) epidermal (ΔpH -1.5) and Arabidopsis thaliana root cells (ΔpH -2.1). The average pH in VSR compartments was intermediate between that of the trans-Golgi and the vacuole. Combining pH measurements with in vivo colocalization experiments, we found that the trans-Golgi network had an acidic pH of 6.1, while the prevacuole and late prevacuole were both more alkaline, with pH of 6.6 and 7.1, respectively. We also showed that endosomal pH, and subsequently vacuolar trafficking of soluble proteins, requires both vacuolar-type H(+) ATPase-dependent acidification as well as proton efflux mediated at least by the activity of endosomal sodium/proton NHX-type antiporters.

Extensin network formation in Vitis vinifera callus cells is an essential and causal event in rapid and H2O2-induced reduction in primary cell wall hydration

PubMed Central

2011-01-01

Background Extensin deposition is considered important for the correct assembly and biophysical properties of primary cell walls, with consequences to plant resistance to pathogens, tissue morphology, cell adhesion and extension growth. However, evidence for a direct and causal role for the extensin network formation in changes to cell wall properties has been lacking. Results Hydrogen peroxide treatment of grapevine (Vitis vinifera cv. Touriga) callus cell walls was seen to induce a marked reduction in their hydration and thickness. An analysis of matrix proteins demonstrated this occurs with the insolubilisation of an abundant protein, GvP1, which displays a primary structure and post-translational modifications typical of dicotyledon extensins. The hydration of callus cell walls free from saline-soluble proteins did not change in response to H2O2, but fully regained this capacity after addition of extensin-rich saline extracts. To assay the specific contribution of GvP1 cross-linking and other wall matrix proteins to the reduction in hydration, GvP1 levels in cell walls were manipulated in vitro by binding selected fractions of extracellular proteins and their effect on wall hydration during H2O2 incubation assayed. Conclusions This approach allowed us to conclude that a peroxidase-mediated formation of a covalently linked network of GvP1 is essential and causal in the reduction of grapevine callus wall hydration in response to H2O2. Importantly, this approach also indicated that extensin network effects on hydration was only partially irreversible and remained sensitive to changes in matrix charge. We discuss this mechanism and the importance of these changes to primary wall properties in the light of extensin distribution in dicotyledons. PMID:21672244

Network correlates of sexual health advice seeking and substance use among members of the Los Angeles House and Ball communities

PubMed Central

Holloway, Ian W.; Schrager, Sheree M.; Wong, Carolyn F.; Dunlap, Shannon L.; Kipke, Michele D.

2014-01-01

House and Ball communities (HBCs), represent a prime context for human immunodeficiency virus prevention with African American young men who have sex with men and transgender persons. This study sought to understand the composition and function of social support and sexual networks of HBC members in Los Angeles, California (N = 263). Participants were recruited using venue-based sampling and asked to report on sexual health advice seeking, alcohol use and illicit substance use. Participants were more likely to seek sexual health advice from social support network members compared with sexual network members [odds ratio (OR): 2.50, P < 0.001]. HBC members were more likely to get drunk (OR: 1.57; P < 0.05) and use illicit substances (OR: 1.87; P < 0.10) with House members and sexual network members compared with non-House members and social support network members. Health promotion programs tailored for the HBC should encourage open communication regarding sexual health; these interventions must include information about the role of substance use in sexual risk taking. PMID:24452228

Performance effects of irregular communications patterns on massively parallel multiprocessors

NASA Technical Reports Server (NTRS)

Saltz, Joel; Petiton, Serge; Berryman, Harry; Rifkin, Adam

1991-01-01

A detailed study of the performance effects of irregular communications patterns on the CM-2 was conducted. The communications capabilities of the CM-2 were characterized under a variety of controlled conditions. In the process of carrying out the performance evaluation, extensive use was made of a parameterized synthetic mesh. In addition, timings with unstructured meshes generated for aerodynamic codes and a set of sparse matrices with banded patterns on non-zeroes were performed. This benchmarking suite stresses the communications capabilities of the CM-2 in a range of different ways. Benchmark results demonstrate that it is possible to make effective use of much of the massive concurrency available in the communications network.

Dramatic changes in 67 miRNAs during initiation of first wave of spermatogenesis in Mus musculus testis: global regulatory insights generated by miRNA-mRNA network analysis.

PubMed

Sree, Sreesha; Radhakrishnan, Karthika; Indu, Sivankutty; Kumar, Pradeep G

2014-09-01

We mapped global changes in miRNA and mRNA profiles spanning the first wave of spermatogenesis using prepubertal (Postnatal Day 8 [P8]), pubertal (P16), and adolescent (P24) Mus musculus testes and identified the differential expression of 67 miRNAs and 8226 mRNAs. These two data sets were integrated into miRNA-dependent regulatory networks based on miRWalk predictions. In a network representing the P8 to P16 transition, downregulation of four miRNAs and upregulation of 19 miRNAs were linked with 81 upregulated target mRNAs and 228 downregulated target mRNAs, respectively. Furthermore, during the P16 to P24 transition, two miRNAs were downregulated, and eight miRNAs were upregulated, which linked with 64 upregulated mRNAs and 389 downregulated mRNAs, respectively. Only three of the miRNAs present in the network (miR-34b-5p, miR-34c, and miR-449a) showed a progressive increase from P8 through P16 to P24, while the remaining miRNAs in the network showed statistically significant changes in their levels either during the P8 to P16 transition or during the P16 to P24 transition. Analysis of the chromosomal location of these differentially expressed miRNAs showed that 14 out of 25 miRNAs upregulated from P8 to P16, and 18 out of 40 miRNAs upregulated from P8 to P24 were X-linked. This is suggestive of their escape from meiotic sex chromosome inactivation and postmeiotic sex chromatin. This integrated network of miRNA-level and mRNA-level changes in mouse testis during the first wave of spermatogenesis is expected to build a base for evaluating the role of miRNA-mediated gene expression regulation in maturing mammalian testis. © 2014 by the Society for the Study of Reproduction, Inc.

Image Theory: Policies, Goals, Strategies and Tactics in Decision Making.

DTIC Science & Technology

1986-03-01

Harvard Busin *; s Review. July/August, 49-61. Mintzberg, H., Rausingham, D. & Theoret, A. (1976). The structure of unstructured decision processes...coveEuDEo lmagle Theory: Policies, Goals, Strategies Technical Report 6. EFRIGDG REPORT NUME-f 7 A~NOR~eJTR 86-3 𔄁ATO, I CONTRACT OR GRANT NUMBER( s ) Lee Roy...Identity by block niumber) De’Cis ,ion Makinlg Doubt P0 li ci es Uncerta inty L I Li CTIs SbDject ive Probability Tact ic~ s C o 00 AOSTHACT (Conan.uo an

Error-correcting codes on scale-free networks

NASA Astrophysics Data System (ADS)

Kim, Jung-Hoon; Ko, Young-Jo

2004-06-01

We investigate the potential of scale-free networks as error-correcting codes. We find that irregular low-density parity-check codes with the highest performance known to date have degree distributions well fitted by a power-law function p (k) ˜ k-γ with γ close to 2, which suggests that codes built on scale-free networks with appropriate power exponents can be good error-correcting codes, with a performance possibly approaching the Shannon limit. We demonstrate for an erasure channel that codes with a power-law degree distribution of the form p (k) = C (k+α)-γ , with k⩾2 and suitable selection of the parameters α and γ , indeed have very good error-correction capabilities.

Carboxylated Fullerene at the Oil/Water Interface.

PubMed

Li, Rongqiang; Chai, Yu; Jiang, Yufeng; Ashby, Paul D; Toor, Anju; Russell, Thomas P

2017-10-04

The self-assembly of carboxylated fullerene with poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) with different molecular weights, poly-2-vinylpyridine, and amine-terminated polystyrene, at the interface between toluene and water was investigated. For all values of the pH, the functionalized fullerene interacted with the polymers at the water/toluene interface, forming a nanoparticle network, reducing the interfacial tension. At pH values of 4.84 and 7.8, robust, elastic films were formed at the interface, such that hollow tubules could be formed in situ when an aqueous solution of the functionalized fullerene was jetted into a toluene solution of PS-b-P2VP at a pH of 4.84. With variation of the pH, the mechanical properties of the fullerene/polymer assemblies can be varied by tuning the strength of the interactions between the functionalized fullerenes and the PS-b-P2VP.

Dynamic Models of Insurgent Activity

DTIC Science & Technology

2014-05-19

Martin Short, P. Jeffrey Brantingham, Frederick Schoenberg, George Tita . Self-Exciting Point Process Modeling of Crime, Journal of the American...Mohler, P. J. Brantingham, G. E. Tita . Gang rivalry dynamics via coupled point process networks, Discrete and Continuous Dynamical Systems - Series...8532-2-1 Laura Smith, Andrea Bertozzi, P. Jeffrey Brantingham, George Tita , Matthew Valasik. ADAPTATION OF AN ECOLOGICAL TERRITORIAL MODEL TOSTREET

Genetically encoded proton sensors reveal activity-dependent pH changes in neurons.

PubMed

Raimondo, Joseph V; Irkle, Agnese; Wefelmeyer, Winnie; Newey, Sarah E; Akerman, Colin J

2012-01-01

The regulation of hydrogen ion concentration (pH) is fundamental to cell viability, metabolism, and enzymatic function. Within the nervous system, the control of pH is also involved in diverse and dynamic processes including development, synaptic transmission, and the control of network excitability. As pH affects neuronal activity, and can also itself be altered by neuronal activity, the existence of tools to accurately measure hydrogen ion fluctuations is important for understanding the role pH plays under physiological and pathological conditions. Outside of their use as a marker of synaptic release, genetically encoded pH sensors have not been utilized to study hydrogen ion fluxes associated with network activity. By combining whole-cell patch clamp with simultaneous two-photon or confocal imaging, we quantified the amplitude and time course of neuronal, intracellular, acidic transients evoked by epileptiform activity in two separate in vitro models of temporal lobe epilepsy. In doing so, we demonstrate the suitability of three genetically encoded pH sensors: deGFP4, E(2)GFP, and Cl-sensor for investigating activity-dependent pH changes at the level of single neurons.

Network Centric Operations (NCO) Case Study. The British Approach to Low-Intensity Operations: Part 2

DTIC Science & Technology

2007-02-12

Imperial War Museum Sound Archive, Accession No. 16397 (6 January 1996 ) 46 Jackson, p .45 47 Nagl, p .66-7 48 Stubbs, p .71 49 Nagl, p .93 Part II 16...Coogan, The Troubles, (London: Arrow, 1996 ), p .145 Part II 61 of 246 but there really appeared to be nothing in between to provide workable...Psychological Ops Capability Since 1945’, British Army Review, December 1996 , p .5 Part II 62 of 246 weakness caused by the lack of both numbers and

Shadoo/PrP (Sprn0/0/Prnp0/0) double knockout mice

PubMed Central

Daude, Nathalie; Westaway, David

2012-01-01

Shadoo (Sho) is a brain glycoprotein with similarities to the unstructured region of PrPC. Frameshift alleles of the Sho gene, Sprn, are reported in variant Creutzfeldt-Jakob disease (vCJD) patients while Sprn mRNA knockdown in PrP-null (Prnp0/0) embryos produces lethality, advancing Sho as the hypothetical PrP-like “pi” protein. Also, Sho levels are reduced as misfolded PrP accumulates during prion infections. To penetrate these issues we created Sprn null alleles (Daude et al., Proc. Natl. Acad. Sci USA 2012; 109(23): 9035–40). Results from the challenge of Sprn null and TgSprn transgenic mice with rodent-adapted prions coalesce to define downregulation of Sho as a “tracer” for the formation of misfolded PrP. However, classical BSE and rodent-adapted BSE isolates may behave differently, as they do for other facets of the pathogenic process, and this intriguing variation warrants closer scrutiny. With regards to physiological function, double knockout mice (Sprn0/0/Prnp0/0) mice survived to over 600 d of age. This suggests that Sho is not pi, or, given the accumulating data for many activities for PrPC, that the pi hypothesis invoking a discrete signaling pathway to maintain neuronal viability is no longer tenable. PMID:22929230

pH-dependent and pH-independent self-assembling behavior of surfactant-like peptides

NASA Astrophysics Data System (ADS)

Gurevich, Leonid; Fojan, Peter

2012-02-01

Self-assembly of amphiphilic peptides designed during the last years by several research groups leads to a large variety of 3D-structures that already found applications in stabilization of large protein complexes, cell culturing systems etc. In this report, we present synthesis and characterization of two novel families of amphiphilic peptides KAn and KAnW (n=6,5,4) that exhibits clear charge separation controllable by pH of the environment. As the pH changes from acidic to basic, the charge on the ends of the peptide molecule varies eventually leading to reorganization of KAn micelles and even micellar inversion. On contrary, the bulky geometry of the tryptophan residue in KAnW limits the variation of the surfactant parameter and hence largely prevents assembly into spherical or cylindrical micelles while favouring flatter geometries. The studied short peptide families demonstrate formation of ordered aggregates with well-defined secondary structure from short unstructured peptides and provide a simple system where factors responsible for self-assembly can be singled out and studied one by one. The ability to control the shape and structure of peptide aggregates can provide basis for novel designer pH sensitive materials including drug delivery and controlled release systems.

Inability of Prevotella bryantii to Form a Functional Shine-Dalgarno Interaction Reflects Unique Evolution of Ribosome Binding Sites in Bacteroidetes

PubMed Central

Accetto, Tomaž; Avguštin, Gorazd

2011-01-01

The Shine-Dalgarno (SD) sequence is a key element directing the translation to initiate at the authentic start codons and also enabling translation initiation to proceed in 5′ untranslated mRNA regions (5′-UTRs) containing moderately strong secondary structures. Bioinformatic analysis of almost forty genomes from the major bacterial phylum Bacteroidetes revealed, however, a general absence of SD sequence, drop in GC content and consequently reduced tendency to form secondary structures in 5′-UTRs. The experiments using the Prevotella bryantii TC1-1 expression system were in agreement with these findings: neither addition nor omission of SD sequence in the unstructured 5′-UTR affected the level of the reporter protein, non-specific nuclease NucB. Further, NucB level in P. bryantii TC1-1, contrary to hMGFP level in Escherichia coli, was five times lower when SD sequence formed part of the secondary structure with a folding energy -5,2 kcal/mol. Also, the extended SD sequences did not affect protein levels as in E. coli. It seems therefore that a functional SD interaction does not take place during the translation initiation in P. bryanttii TC1-1 and possibly other members of phylum Bacteroidetes although the anti SD sequence is present in 16S rRNA genes of their genomes. We thus propose that in the absence of the SD sequence interaction, the selection of genuine start codons in Bacteroidetes is accomplished by binding of ribosomal protein S1 to unstructured 5′-UTR as opposed to coding region which is inaccessible due to mRNA secondary structure. Additionally, we found that sequence logos of region preceding the start codons may be used as taxonomical markers. Depending on whether complete sequence logo or only part of it, such as information content and base proportion at specific positions, is used, bacterial genera or families and in some cases even bacterial phyla can be distinguished. PMID:21857964

Robustness of the p53 network and biological hackers.

PubMed

Dartnell, Lewis; Simeonidis, Evangelos; Hubank, Michael; Tsoka, Sophia; Bogle, I David L; Papageorgiou, Lazaros G

2005-06-06

The p53 protein interaction network is crucial in regulating the metazoan cell cycle and apoptosis. Here, the robustness of the p53 network is studied by analyzing its degeneration under two modes of attack. Linear Programming is used to calculate average path lengths among proteins and the network diameter as measures of functionality. The p53 network is found to be robust to random loss of nodes, but vulnerable to a targeted attack against its hubs, as a result of its architecture. The significance of the results is considered with respect to mutational knockouts of proteins and the directed attacks mounted by tumour inducing viruses.

Nocturnal insomnia symptoms and stress-induced cognitive intrusions in risk for depression: A 2-year prospective study

PubMed Central

Pillai, Vivek; Drake, Christopher L.

2018-01-01

Nearly half of US adults endorse insomnia symptoms. Sleep problems increase risk for depression during stress, but the mechanisms are unclear. During high stress, individuals having difficulty falling or staying asleep may be vulnerable to cognitive intrusions after stressful events, given that the inability to sleep creates a period of unstructured and socially isolated time in bed. We investigated the unique and combined effects of insomnia symptoms and stress-induced cognitive intrusions on risk for incident depression. 1126 non-depressed US adults with no history of DSM-5 insomnia disorder completed 3 annual web-based surveys on sleep, stress, and depression. We examined whether nocturnal insomnia symptoms and stress-induced cognitive intrusions predicted depression 1y and 2y later. Finally, we compared depression-risk across four groups: non-perseverators with good sleep, non-perseverators with insomnia symptoms, perseverators with good sleep, and perseverators with insomnia symptoms. Insomnia symptoms (β = .10–.13, p < .001) and cognitive intrusions (β = .19–.20, p < .001) predicted depression severity 1y and 2y later. Depression incidence across 2 years was 6.2%. Perseverators with insomnia had the highest rates of depression (13.0%), whereas good sleeping non-perseverators had the lowest rates (3.3%, Relative Risk = 3.94). Perseverators with sleep latency >30 m reported greater depression than good sleeping perseverators (t = 2.09, p < .04). Cognitive intrusions following stress creates a depressogenic mindset, and nocturnal wakefulness may augment the effects of cognitive arousal on depression development. Poor sleepers may be especially vulnerable to cognitive intrusions when having difficulty initiating sleep. As treatable behaviors, nighttime wakefulness and cognitive arousal may be targeted to reduce risk for depression in poor sleepers. PMID:29438400

Nocturnal insomnia symptoms and stress-induced cognitive intrusions in risk for depression: A 2-year prospective study.

PubMed

Kalmbach, David A; Pillai, Vivek; Drake, Christopher L

2018-01-01

Nearly half of US adults endorse insomnia symptoms. Sleep problems increase risk for depression during stress, but the mechanisms are unclear. During high stress, individuals having difficulty falling or staying asleep may be vulnerable to cognitive intrusions after stressful events, given that the inability to sleep creates a period of unstructured and socially isolated time in bed. We investigated the unique and combined effects of insomnia symptoms and stress-induced cognitive intrusions on risk for incident depression. 1126 non-depressed US adults with no history of DSM-5 insomnia disorder completed 3 annual web-based surveys on sleep, stress, and depression. We examined whether nocturnal insomnia symptoms and stress-induced cognitive intrusions predicted depression 1y and 2y later. Finally, we compared depression-risk across four groups: non-perseverators with good sleep, non-perseverators with insomnia symptoms, perseverators with good sleep, and perseverators with insomnia symptoms. Insomnia symptoms (β = .10-.13, p < .001) and cognitive intrusions (β = .19-.20, p < .001) predicted depression severity 1y and 2y later. Depression incidence across 2 years was 6.2%. Perseverators with insomnia had the highest rates of depression (13.0%), whereas good sleeping non-perseverators had the lowest rates (3.3%, Relative Risk = 3.94). Perseverators with sleep latency >30 m reported greater depression than good sleeping perseverators (t = 2.09, p < .04). Cognitive intrusions following stress creates a depressogenic mindset, and nocturnal wakefulness may augment the effects of cognitive arousal on depression development. Poor sleepers may be especially vulnerable to cognitive intrusions when having difficulty initiating sleep. As treatable behaviors, nighttime wakefulness and cognitive arousal may be targeted to reduce risk for depression in poor sleepers.

Short range structure of 0.35Sb2O3-0.65(Li2O-P2O5) glass: A neutron diffraction study

NASA Astrophysics Data System (ADS)

Shinde, A. B.; Krishna, P. S. R.

2018-04-01

Neutron diffraction studies on Li2O-P2O5 and 0.35Sb2O3-0.65(Li2O-P2O5) glass are performed up to a Qmax of 15 Å-1 on the High-Q diffractometer, Dhruva. MCGR method is used to find pair correlation functions (g(r)) functions from experimentally obtained S(Q). We found that the Li-O and first Sb-O correlations to be around 2.04 Å & 2.15 Å. The O-O correlation from Phosphate & Antimony networks are found to be around 2.7 Å. The short range order of Sb is similar to its crystalline polymorph of valentinite instead of senarmonite. The short range order and network connectivity in this glass implies a structure composed of chains of corner sharing SbO3 pyramidal units connected to PO4 tetrahedra while Li acts as a modifier.

Identifying key genes associated with acute myocardial infarction.

PubMed

Cheng, Ming; An, Shoukuan; Li, Junquan

2017-10-01

This study aimed to identify key genes associated with acute myocardial infarction (AMI) by reanalyzing microarray data. Three gene expression profile datasets GSE66360, GSE34198, and GSE48060 were downloaded from GEO database. After data preprocessing, genes without heterogeneity across different platforms were subjected to differential expression analysis between the AMI group and the control group using metaDE package. P < .05 was used as the cutoff for a differentially expressed gene (DEG). The expression data matrices of DEGs were imported in ReactomeFIViz to construct a gene functional interaction (FI) network. Then, DEGs in each module were subjected to pathway enrichment analysis using DAVID. MiRNAs and transcription factors predicted to regulate target DEGs were identified. Quantitative real-time polymerase chain reaction (RT-PCR) was applied to verify the expression of genes. A total of 913 upregulated genes and 1060 downregulated genes were identified in the AMI group. A FI network consists of 21 modules and DEGs in 12 modules were significantly enriched in pathways. The transcription factor-miRNA-gene network contains 2 transcription factors FOXO3 and MYBL2, and 2 miRNAs hsa-miR-21-5p and hsa-miR-30c-5p. RT-PCR validations showed that expression levels of FOXO3 and MYBL2 were significantly increased in AMI, and expression levels of hsa-miR-21-5p and hsa-miR-30c-5p were obviously decreased in AMI. A total of 41 DEGs, such as SOCS3, VAPA, and COL5A2, are speculated to have roles in the pathogenesis of AMI; 2 transcription factors FOXO3 and MYBL2, and 2 miRNAs hsa-miR-21-5p and hsa-miR-30c-5p may be involved in the regulation of the expression of these DEGs.

Identifying key genes associated with acute myocardial infarction

PubMed Central

Cheng, Ming; An, Shoukuan; Li, Junquan

2017-01-01

Abstract Background: This study aimed to identify key genes associated with acute myocardial infarction (AMI) by reanalyzing microarray data. Methods: Three gene expression profile datasets GSE66360, GSE34198, and GSE48060 were downloaded from GEO database. After data preprocessing, genes without heterogeneity across different platforms were subjected to differential expression analysis between the AMI group and the control group using metaDE package. P < .05 was used as the cutoff for a differentially expressed gene (DEG). The expression data matrices of DEGs were imported in ReactomeFIViz to construct a gene functional interaction (FI) network. Then, DEGs in each module were subjected to pathway enrichment analysis using DAVID. MiRNAs and transcription factors predicted to regulate target DEGs were identified. Quantitative real-time polymerase chain reaction (RT-PCR) was applied to verify the expression of genes. Result: A total of 913 upregulated genes and 1060 downregulated genes were identified in the AMI group. A FI network consists of 21 modules and DEGs in 12 modules were significantly enriched in pathways. The transcription factor-miRNA-gene network contains 2 transcription factors FOXO3 and MYBL2, and 2 miRNAs hsa-miR-21-5p and hsa-miR-30c-5p. RT-PCR validations showed that expression levels of FOXO3 and MYBL2 were significantly increased in AMI, and expression levels of hsa-miR-21–5p and hsa-miR-30c-5p were obviously decreased in AMI. Conclusion: A total of 41 DEGs, such as SOCS3, VAPA, and COL5A2, are speculated to have roles in the pathogenesis of AMI; 2 transcription factors FOXO3 and MYBL2, and 2 miRNAs hsa-miR-21-5p and hsa-miR-30c-5p may be involved in the regulation of the expression of these DEGs. PMID:29049183

Diffusion, capture and recycling of SCAR/WAVE and Arp2/3 complexes observed in cells by single-molecule imaging.

PubMed

Millius, Arthur; Watanabe, Naoki; Weiner, Orion D

2012-03-01

The SCAR/WAVE complex drives lamellipodium formation by enhancing actin nucleation by the Arp2/3 complex. Phosphoinositides and Rac activate the SCAR/WAVE complex, but how SCAR/WAVE and Arp2/3 complexes converge at sites of nucleation is unknown. We analyzed the single-molecule dynamics of WAVE2 and p40 (subunits of the SCAR/WAVE and Arp2/3 complexes, respectively) in XTC cells. We observed lateral diffusion of both proteins and captured the transition of p40 from diffusion to network incorporation. These results suggest that a diffusive 2D search facilitates binding of the Arp2/3 complex to actin filaments necessary for nucleation. After nucleation, the Arp2/3 complex integrates into the actin network and undergoes retrograde flow, which results in its broad distribution throughout the lamellipodium. By contrast, the SCAR/WAVE complex is more restricted to the cell periphery. However, with single-molecule imaging, we also observed WAVE2 molecules undergoing retrograde motion. WAVE2 and p40 have nearly identical speeds, lifetimes and sites of network incorporation. Inhibition of actin retrograde flow does not prevent WAVE2 association and disassociation with the membrane but does inhibit WAVE2 removal from the actin cortex. Our results suggest that membrane binding and diffusion expedites the recruitment of nucleation factors to a nucleation site independent of actin assembly, but after network incorporation, ongoing actin polymerization facilitates recycling of SCAR/WAVE and Arp2/3 complexes.

Diffusion, capture and recycling of SCAR/WAVE and Arp2/3 complexes observed in cells by single-molecule imaging

PubMed Central

Millius, Arthur; Watanabe, Naoki; Weiner, Orion D.

2012-01-01

The SCAR/WAVE complex drives lamellipodium formation by enhancing actin nucleation by the Arp2/3 complex. Phosphoinositides and Rac activate the SCAR/WAVE complex, but how SCAR/WAVE and Arp2/3 complexes converge at sites of nucleation is unknown. We analyzed the single-molecule dynamics of WAVE2 and p40 (subunits of the SCAR/WAVE and Arp2/3 complexes, respectively) in XTC cells. We observed lateral diffusion of both proteins and captured the transition of p40 from diffusion to network incorporation. These results suggest that a diffusive 2D search facilitates binding of the Arp2/3 complex to actin filaments necessary for nucleation. After nucleation, the Arp2/3 complex integrates into the actin network and undergoes retrograde flow, which results in its broad distribution throughout the lamellipodium. By contrast, the SCAR/WAVE complex is more restricted to the cell periphery. However, with single-molecule imaging, we also observed WAVE2 molecules undergoing retrograde motion. WAVE2 and p40 have nearly identical speeds, lifetimes and sites of network incorporation. Inhibition of actin retrograde flow does not prevent WAVE2 association and disassociation with the membrane but does inhibit WAVE2 removal from the actin cortex. Our results suggest that membrane binding and diffusion expedites the recruitment of nucleation factors to a nucleation site independent of actin assembly, but after network incorporation, ongoing actin polymerization facilitates recycling of SCAR/WAVE and Arp2/3 complexes. PMID:22349699

Sorption of CO 2 in a hydrogen-bonded diamondoid network of sulfonylcalix[4]arene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinnwell, Michael A.; Atwood, Jerry L.; Thallapally, Praveen K.

An organic material, p-tert-butyltetrasulfonylcalix[4]arene, self-assembles via hydrogen bonding to form a diamondoid supramolecular network. Possessing discrete, zero-dimensional (0D) microcavities, the thiacalixarene derivative adsorbs CO2 at high pressures

From complex questionnaire and interviewing data to intelligent Bayesian Network models for medical decision support

PubMed Central

Constantinou, Anthony Costa; Fenton, Norman; Marsh, William; Radlinski, Lukasz

2016-01-01

Objectives 1) To develop a rigorous and repeatable method for building effective Bayesian network (BN) models for medical decision support from complex, unstructured and incomplete patient questionnaires and interviews that inevitably contain examples of repetitive, redundant and contradictory responses; 2) To exploit expert knowledge in the BN development since further data acquisition is usually not possible; 3) To ensure the BN model can be used for interventional analysis; 4) To demonstrate why using data alone to learn the model structure and parameters is often unsatisfactory even when extensive data is available. Method The method is based on applying a range of recent BN developments targeted at helping experts build BNs given limited data. While most of the components of the method are based on established work, its novelty is that it provides a rigorous consolidated and generalised framework that addresses the whole life-cycle of BN model development. The method is based on two original and recent validated BN models in forensic psychiatry, known as DSVM-MSS and DSVM-P. Results When employed with the same datasets, the DSVM-MSS demonstrated competitive to superior predictive performance (AUC scores 0.708 and 0.797) against the state-of-the-art (AUC scores ranging from 0.527 to 0.705), and the DSVM-P demonstrated superior predictive performance (cross-validated AUC score of 0.78) against the state-of-the-art (AUC scores ranging from 0.665 to 0.717). More importantly, the resulting models go beyond improving predictive accuracy and into usefulness for risk management purposes through intervention, and enhanced decision support in terms of answering complex clinical questions that are based on unobserved evidence. Conclusions This development process is applicable to any application domain which involves large-scale decision analysis based on such complex information, rather than based on data with hard facts, and in conjunction with the incorporation of expert knowledge for decision support via intervention. The novelty extends to challenging the decision scientists to reason about building models based on what information is really required for inference, rather than based on what data is available and hence, forces decision scientists to use available data in a much smarter way. PMID:26830286

From complex questionnaire and interviewing data to intelligent Bayesian network models for medical decision support.

PubMed

Constantinou, Anthony Costa; Fenton, Norman; Marsh, William; Radlinski, Lukasz

2016-02-01

(1) To develop a rigorous and repeatable method for building effective Bayesian network (BN) models for medical decision support from complex, unstructured and incomplete patient questionnaires and interviews that inevitably contain examples of repetitive, redundant and contradictory responses; (2) To exploit expert knowledge in the BN development since further data acquisition is usually not possible; (3) To ensure the BN model can be used for interventional analysis; (4) To demonstrate why using data alone to learn the model structure and parameters is often unsatisfactory even when extensive data is available. The method is based on applying a range of recent BN developments targeted at helping experts build BNs given limited data. While most of the components of the method are based on established work, its novelty is that it provides a rigorous consolidated and generalised framework that addresses the whole life-cycle of BN model development. The method is based on two original and recent validated BN models in forensic psychiatry, known as DSVM-MSS and DSVM-P. When employed with the same datasets, the DSVM-MSS demonstrated competitive to superior predictive performance (AUC scores 0.708 and 0.797) against the state-of-the-art (AUC scores ranging from 0.527 to 0.705), and the DSVM-P demonstrated superior predictive performance (cross-validated AUC score of 0.78) against the state-of-the-art (AUC scores ranging from 0.665 to 0.717). More importantly, the resulting models go beyond improving predictive accuracy and into usefulness for risk management purposes through intervention, and enhanced decision support in terms of answering complex clinical questions that are based on unobserved evidence. This development process is applicable to any application domain which involves large-scale decision analysis based on such complex information, rather than based on data with hard facts, and in conjunction with the incorporation of expert knowledge for decision support via intervention. The novelty extends to challenging the decision scientists to reason about building models based on what information is really required for inference, rather than based on what data is available and hence, forces decision scientists to use available data in a much smarter way. Copyright © 2016 Elsevier B.V. All rights reserved.

Overrepresentation of glutamate signaling in Alzheimer's disease: network-based pathway enrichment using meta-analysis of genome-wide association studies.

PubMed

Pérez-Palma, Eduardo; Bustos, Bernabé I; Villamán, Camilo F; Alarcón, Marcelo A; Avila, Miguel E; Ugarte, Giorgia D; Reyes, Ariel E; Opazo, Carlos; De Ferrari, Giancarlo V

2014-01-01

Genome-wide association studies (GWAS) have successfully identified several risk loci for Alzheimer's disease (AD). Nonetheless, these loci do not explain the entire susceptibility of the disease, suggesting that other genetic contributions remain to be identified. Here, we performed a meta-analysis combining data of 4,569 individuals (2,540 cases and 2,029 healthy controls) derived from three publicly available GWAS in AD and replicated a broad genomic region (>248,000 bp) associated with the disease near the APOE/TOMM40 locus in chromosome 19. To detect minor effect size contributions that could help to explain the remaining genetic risk, we conducted network-based pathway analyses either by extracting gene-wise p-values (GW), defined as the single strongest association signal within a gene, or calculated a more stringent gene-based association p-value using the extended Simes (GATES) procedure. Comparison of these strategies revealed that ontological sub-networks (SNs) involved in glutamate signaling were significantly overrepresented in AD (p<2.7×10(-11), p<1.9×10(-11); GW and GATES, respectively). Notably, glutamate signaling SNs were also found to be significantly overrepresented (p<5.1×10(-8)) in the Alzheimer's disease Neuroimaging Initiative (ADNI) study, which was used as a targeted replication sample. Interestingly, components of the glutamate signaling SNs are coordinately expressed in disease-related tissues, which are tightly related to known pathological hallmarks of AD. Our findings suggest that genetic variation within glutamate signaling contributes to the remaining genetic risk of AD and support the notion that functional biological networks should be targeted in future therapies aimed to prevent or treat this devastating neurological disorder.

Overrepresentation of Glutamate Signaling in Alzheimer's Disease: Network-Based Pathway Enrichment Using Meta-Analysis of Genome-Wide Association Studies

PubMed Central

Villamán, Camilo F.; Alarcón, Marcelo A.; Avila, Miguel E.; Ugarte, Giorgia D.; Reyes, Ariel E.; Opazo, Carlos; De Ferrari, Giancarlo V.

2014-01-01

Genome-wide association studies (GWAS) have successfully identified several risk loci for Alzheimer's disease (AD). Nonetheless, these loci do not explain the entire susceptibility of the disease, suggesting that other genetic contributions remain to be identified. Here, we performed a meta-analysis combining data of 4,569 individuals (2,540 cases and 2,029 healthy controls) derived from three publicly available GWAS in AD and replicated a broad genomic region (>248,000 bp) associated with the disease near the APOE/TOMM40 locus in chromosome 19. To detect minor effect size contributions that could help to explain the remaining genetic risk, we conducted network-based pathway analyses either by extracting gene-wise p-values (GW), defined as the single strongest association signal within a gene, or calculated a more stringent gene-based association p-value using the extended Simes (GATES) procedure. Comparison of these strategies revealed that ontological sub-networks (SNs) involved in glutamate signaling were significantly overrepresented in AD (p<2.7×10−11, p<1.9×10−11; GW and GATES, respectively). Notably, glutamate signaling SNs were also found to be significantly overrepresented (p<5.1×10−8) in the Alzheimer's disease Neuroimaging Initiative (ADNI) study, which was used as a targeted replication sample. Interestingly, components of the glutamate signaling SNs are coordinately expressed in disease-related tissues, which are tightly related to known pathological hallmarks of AD. Our findings suggest that genetic variation within glutamate signaling contributes to the remaining genetic risk of AD and support the notion that functional biological networks should be targeted in future therapies aimed to prevent or treat this devastating neurological disorder. PMID:24755620

Binding of peptides with basic and aromatic residues to bilayer membranes: phenylalanine in the myristoylated alanine-rich C kinase substrate effector domain penetrates into the hydrophobic core of the bilayer.

PubMed

Zhang, Wenyi; Crocker, Evan; McLaughlin, Stuart; Smith, Steven O

2003-06-13

Electrostatic interactions with positively charged regions of membrane-associated proteins such as myristoylated alanine-rich C kinase substrate (MARCKS) may have a role in regulating the level of free phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in plasma membranes. Both the MARCKS protein and a peptide corresponding to the effector domain (an unstructured region that contains 13 basic residues and 5 phenylalanines), MARCKS-(151-175), laterally sequester the polyvalent lipid PI(4,5)P2 in the plane of a bilayer membrane with high affinity. We used high resolution magic angle spinning NMR to establish the location of MARCKS-(151-175) in membrane bilayers, which is necessary to understand the sequestration mechanism. Measurements of cross-relaxation rates in two-dimensional nuclear Overhauser enhancement spectroscopy NMR experiments show that the five Phe rings of MARCKS-(151-175) penetrate into the acyl chain region of phosphatidylcholine bilayers containing phosphatidylglycerol or PI(4,5)P2. Specifically, we observed strong cross-peaks between the aromatic protons of the Phe rings and the acyl chain protons of the lipids, even for very short (50 ms) mixing times. The position of the Phe rings implies that the adjacent positively charged amino acids in the peptide are close to the level of the negatively charged lipid phosphates. The deep location of the MARCKS peptide in the polar head group region should enhance its electrostatic sequestration of PI(4,5)P2 by an "image charge" mechanism. Moreover, this location has interesting implications for membrane curvature and local surface pressure effects and may be relevant to a wide variety of other proteins with basic-aromatic clusters, such as phospholipase D, GAP43, SCAMP2, and the N-methyl-d-aspartate receptor.

Effects on Pulmonary Vascular Mechanics of Two Different Lung-Protective Ventilation Strategies in an Experimental Model of Acute Respiratory Distress Syndrome.

PubMed

Santos, Arnoldo; Gomez-Peñalver, Eva; Monge-Garcia, M Ignacio; Retamal, Jaime; Borges, João Batista; Tusman, Gerardo; Hedenstierna, Goran; Larsson, Anders; Suarez-Sipmann, Fernando

2017-11-01

To compare the effects of two lung-protective ventilation strategies on pulmonary vascular mechanics in early acute respiratory distress syndrome. Experimental study. University animal research laboratory. Twelve pigs (30.8 ± 2.5 kg). Acute respiratory distress syndrome was induced by repeated lung lavages and injurious mechanical ventilation. Thereafter, animals were randomized to 4 hours ventilation according to the Acute Respiratory Distress Syndrome Network protocol or to an open lung approach strategy. Pressure and flow sensors placed at the pulmonary artery trunk allowed continuous assessment of pulmonary artery resistance, effective elastance, compliance, and reflected pressure waves. Respiratory mechanics and gas exchange data were collected. Acute respiratory distress syndrome led to pulmonary vascular mechanics deterioration. Four hours after randomization, pulmonary vascular mechanics was similar in Acute Respiratory Distress Syndrome Network and open lung approach: resistance (578 ± 252 vs 626 ± 153 dyn.s/cm; p = 0.714), effective elastance, (0.63 ± 0.22 vs 0.58 ± 0.17 mm Hg/mL; p = 0.710), compliance (1.19 ± 0.8 vs 1.50 ± 0.27 mL/mm Hg; p = 0.437), and reflection index (0.36 ± 0.04 vs 0.34 ± 0.09; p = 0.680). Open lung approach as compared to Acute Respiratory Distress Syndrome Network was associated with improved dynamic respiratory compliance (17.3 ± 2.6 vs 10.5 ± 1.3 mL/cm H2O; p < 0.001), driving pressure (9.6 ± 1.3 vs 19.3 ± 2.7 cm H2O; p < 0.001), and venous admixture (0.05 ± 0.01 vs 0.22 ± 0.03, p < 0.001) and lower mean pulmonary artery pressure (26 ± 3 vs 34 ± 7 mm Hg; p = 0.045) despite of using a higher positive end-expiratory pressure (17.4 ± 0.7 vs 9.5 ± 2.4 cm H2O; p < 0.001). Cardiac index, however, was lower in open lung approach (1.42 ± 0.16 vs 2.27 ± 0.48 L/min; p = 0.005). In this experimental model, Acute Respiratory Distress Syndrome Network and open lung approach affected pulmonary vascular mechanics similarly. The use of higher positive end-expiratory pressures in the open lung approach strategy did not worsen pulmonary vascular mechanics, improved lung mechanics, and gas exchange but at the expense of a lower cardiac index.

Improving P2P live-content delivery using SVC

NASA Astrophysics Data System (ADS)

Schierl, T.; Sánchez, Y.; Hellge, C.; Wiegand, T.

2010-07-01

P2P content delivery techniques for video transmission have become of high interest in the last years. With the involvement of client into the delivery process, P2P approaches can significantly reduce the load and cost on servers, especially for popular services. However, previous studies have already pointed out the unreliability of P2P-based live streaming approaches due to peer churn, where peers may ungracefully leave the P2P infrastructure, typically an overlay networks. Peers ungracefully leaving the system cause connection losses in the overlay, which require repair operations. During such repair operations, which typically take a few roundtrip times, no data is received from the lost connection. While taking low delay for fast-channel tune-in into account as a key feature for broadcast-like streaming applications, the P2P live streaming approach can only rely on a certain media pre-buffer during such repair operations. In this paper, multi-tree based Application Layer Multicast as a P2P overlay technique for live streaming is considered. The use of Flow Forwarding (FF), a.k.a. Retransmission, or Forward Error Correction (FEC) in combination with Scalable video Coding (SVC) for concealment during overlay repair operations is shown. Furthermore the benefits of using SVC over the use of AVC single layer transmission are presented.

Postnatal development of Na+-K+-2Cl− co-transporter 1 (NKCC1) and K+-Cl−co-transporter 2 (KCC2) immunoreactivity in multiple brain stem respiratory nuclei of the rat

PubMed Central

Liu, Qiuli; Wong-Riley, Margaret T.T.

2012-01-01

Previously, we reported that in rats, GABAA and glycine receptor immunoreactivity increased markedly in multiple brain stem respiratory nuclei around postnatal days (P) 12–13, a critical period when abrupt neurochemical, metabolic, ventilatory, and electrophysiological changes occur in the respiratory network and when the system is under greater inhibition than excitation. Since Na+-K+-2Cl− co-transporter 1 (NKCC1) and K+-Cl− co-transporter 2 (KCC2) play pivotal roles in determining the responses of GABAA and glycine receptors, we hypothesized that NKCC1 and KCC2 undergo significant changes during the critical period. An in-depth immunohistochemical and single neuron optical densitometric study of neurons in seven respiratory-related nuclei (the pre-Bötzinger complex [PBC], nucleus ambiguus [Amb], hypoglossal nucleus [XII], ventrolateral subnucleus of solitary tract nucleus [NTSVL], retrotrapezoid nucleus/parafacial respiratory group [RTN/pFRG], dorsal motor nucleus of the vagus nerve [DMNX], and inferior olivary nucleus [IO]) and a non-respiratory cuneate nucleus (CN, an internal control) was undertaken in P0–21 rats. Our data revealed that: (1) NKCC1 immunoreactivity exhibited a developmental decrease from P0 to P21 in all eight nuclei examined, being relatively high during the first 1½ postnatal weeks and decreased thereafter. The decrease was abrupt and statistically significant at P12 in the PBC, Amb, and XII; (2) KCC2 immunoreactivity in these eight nuclei showed a developmental increase from P0 to P21; and (3) the significant reduction in NKCC1 and the greater dominance of KCC2 around P12 in multiple respiratory nuclei of the brain stem may form the basis of an enhanced inhibition in the respiratory network during the critical period before the system stabilizes to a more mature state. PMID:22441038

Docking and QSAR comparative studies of polycyclic aromatic hydrocarbons and other procarcinogen interactions with cytochromes P450 1A1 and 1B1.

PubMed

Gonzalez, J; Marchand-Geneste, N; Giraudel, J L; Shimada, T

2012-01-01

To obtain chemical clues on the process of bioactivation by cytochromes P450 1A1 and 1B1, some QSAR studies were carried out based on cellular experiments of the metabolic activation of polycyclic aromatic hydrocarbons and heterocyclic aromatic compounds by those enzymes. Firstly, the 3D structures of cytochromes 1A1 and 1B1 were built using homology modelling with a cytochrome 1A2 template. Using these structures, 32 ligands including heterocyclic aromatic compounds, polycyclic aromatic hydrocarbons and corresponding diols, were docked with LigandFit and CDOCKER algorithms. Binding mode analysis highlighted the importance of hydrophobic interactions and the hydrogen bonding network between cytochrome amino acids and docked molecules. Finally, for each enzyme, multilinear regression and artificial neural network QSAR models were developed and compared. These statistical models highlighted the importance of electronic, structural and energetic descriptors in metabolic activation process, and could be used for virtual screening of ligand databases. In the case of P450 1A1, the best model was obtained with artificial neural network analysis and gave an r (2) of 0.66 and an external prediction [Formula: see text] of 0.73. Concerning P450 1B1, artificial neural network analysis gave a much more robust model, associated with an r (2) value of 0.73 and an external prediction [Formula: see text] of 0.59.

Evaluation of model parameters for growth, tannic acid utilization and tannase production in Bacillus gottheilii M2S2 using polyurethane foam blocks as support.

PubMed

Selvaraj, Subbalaxmi; Vytla, Ramachandra Murty

2017-10-01

Production of tannase from B. gottheilii M2S2 was studied under solid-state fermentation with an optimized medium consisting of polyurethane foam matrix of dimension 40 × 40 × 5 mm, impregnated with a liquid medium comprising (w/v): 4% tannic acid; 2% NH 4 NO 3 ; 0.1% KH 2 PO 4 ; 0.2% MgSO 4 ; 0.1% NaCl and 0.05% CaCl 2 ·2H 2 O in distilled water, having a pH of 4.7. Maximum tannase production of 56.87 U/L was obtained after 32 h of fermentation at 32 °C in static condition. This study deals with the evaluation of unstructured kinetic models to understand the behavior of biomass, tannase production and tannic acid degradation, with the fermentation time. The growth rate of B. gottheilii M2S2 was 0.0703 h -1 at 32 h of fermentation. Product ( Y x/s ) and biomass yield ( Y p/s ) coefficients were estimated as 1.77 U/g of tannic acid and 0.276 g of biomass/g of tannic acid. All the kinetic constants µ , α , β , m and n were evaluated using MATLAB 2015Rb program. The experimental and model-generated data showed a good correlation, which indicated that these models will describe tannase production and fermentation process.

It is all about being popular: the effects of need for popularity on social network site use.

PubMed

Utz, Sonja; Tanis, Martin; Vermeulen, Ivar

2012-01-01

Prior research on predictors of social network site (SNS) use has mainly focused on the Big Five, narcissism, and self-esteem. Results have been inconsistent, and variance explained was rather low. Need for popularity (NfP) might be a better predictor of SNS use, because SNSs are ideal venues for people with a high NfP. Study 1 tested NfP, self-esteem, need to belong, entitlement, and vanity as predictors for a range of SNS behaviors; Study 2 replaced entitlement and vanity with narcissism and added the Big Five as predictors. SNS behaviors assessed were grooming, strategic self-presentation, profile enhancement, disclosure of feelings, routine use of SNS, and number of friends. Results showed that NfP was the strongest and most consistent predictor of SNS behaviors. This pattern indicates that NfP plays an important role in SNSs.

Social networking among upper extremity patients.

PubMed

Rozental, Tamara D; George, Tina M; Chacko, Aron T

2010-05-01

Despite their rising popularity, the health care profession has been slow to embrace social networking sites. These are Web-based initiatives, designed to bring people with common interests or activities under a common umbrella. The purpose of this study is to evaluate social networking patterns among upper extremity patients. A total of 742 anonymous questionnaires were distributed among upper extremity outpatients, with a 62% response rate (462 were completed). Demographic characteristics (gender, age, level of education, employment, type of health insurance, and income stratification) were defined, and data on computer ownership and frequency of social networking use were collected. Social network users and nonusers were compared according to their demographic and socioeconomic characteristics. Our patient cohort consisted of 450 patients. Of those 450 patients, 418 had a high school education or higher, and 293 reported a college or graduate degree. The majority of patients (282) were employed at the time of the survey, and income was evenly distributed among U.S. Census Bureau quintiles. A total of 349 patients reported computer ownership, and 170 reported using social networking sites. When compared to nonusers, social networking users were younger (p<.001), more educated (p<.001), and more likely to be employed (p = .013). Users also had higher income levels (p=0.028) and had high rates of computer ownership (p<.001). Multivariate regression revealed that younger age (p<.001), computer ownership (p<.001), and higher education (p<.001) were independent predictors of social networking use. Most users (n = 114) regularly visit a single site. Facebook was the most popular site visited (n=142), followed by MySpace (n=28) and Twitter (n=16). Of the 450 upper extremity patients in our sample, 170 use social networking sites. Younger age, higher level of education, and computer ownership were associated with social networking use. Physicians should consider expanding their use of social networking sites to reach their online patient populations. Copyright 2010 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

On the interconnection between Natural Time and Network Theory as a tool for predicting extreme events in seismology

NASA Astrophysics Data System (ADS)

Sarlis, N. V.; Skordas, E. S.; Varotsos, P.

2009-12-01

A new time domain, termed natural time χ, has been introduced by the authors[1]. This enables, among others, the distinction of Seismic Electric Signals (SES), which are low frequency geoelectric signals (≤1Hz) characterized by critical dynamics and precede earthquakes, from noise emitted from human made sources[2]. If one analyzes in natural time the seismicity subsequent to the SES by using an appropriately constructed network of earthquakes, the time of the impending mainshock can be identified within a few days[3-8]. The values of natural time specify the nodes of this network. Examples are presented, which include the prediction of the largest earthquake that occurred in Greece during the last twenty five years [9]. These examples provide evidence that natural time in conjunction with network theory is beneficial for the prediction of extreme events in seismology[3-6,8] and volcanology[7]. References: [1] P.A. Varotsos, N.V. Sarlis, and E.S. Skordas, Phys. Rev. E 66 , 011902 (2002). [2] P.A. Varotsos, N.V. Sarlis, and E.S. Skordas, Phys. Rev. E 67 , 021109 (2003); 68 , 031106 (2003); Phys. Rev. Lett. 91, 148501(2003). [3] P.A. Varotsos, N.V. Sarlis, H.K. Tanaka, and E.S. Skordas, Phys. Rev. E 72, 041103 (2005). [4] P. A. Varotsos, N. V. Sarlis, E. S. Skordas, H. K. Tanaka, and M. S. Lazaridou, Phys. Rev. E 73 , 031114 (2006); 74 , 021123 (2006). [5] P. A. Varotsos, N. V. Sarlis, E. S. Skordas, and M. S. Lazaridou, J. Appl. Phys. 103 , 014906 (2008). [6] N. V. Sarlis, E. S. Skordas, M. S. Lazaridou, and P. A. Varotsos, Proc. Jpn. Acad., Ser. B: Phys. Biol. Sci. 84 , 331 (2008) [7] S. Uyeda, M. Kamogawa and H. Tanaka, J. Geophys. Res. 114, B02310 (2009). [8] P. A. Varotsos, N. V. Sarlis and E. S. Skordas, CHAOS 19 , 023114 (2009). [9] Uyeda, S., and Kamogawa, M. Eos Trans. AGU 89 , 363 (2008).

Characterizing networks formed by P. polycephalum

NASA Astrophysics Data System (ADS)

Dirnberger, M.; Mehlhorn, K.

2017-06-01

We present a systematic study of the characteristic vein networks formed by the slime mold P. polycephalum. Our study is based on an extensive set of graph representations of slime mold networks. We analyze a total of 1998 graphs capturing growth and network formation of P. polycephalum as observed in 36 independent, identical, wet-lab experiments. Relying on concepts from graph theory such as face cycles and cuts as well as ideas from percolation theory, we establish a broad collection of individual observables taking into account various complementary aspects of P. polycephalum networks. As a whole, the collection is intended to serve as a specialized knowledge-base providing a comprehensive characterization of P. polycephalum networks. To this end, it contains individual as well as cumulative results for all investigated observables across all available data series, down to the level of single P. polycephalum graphs. Furthermore we include the raw numerical data as well as various plotting and analysis tools to ensure reproducibility and increase the usefulness of the collection. All our results are publicly available in an organized fashion in the slime mold graph repository (Smgr).

Gossip-Based Broadcast

NASA Astrophysics Data System (ADS)

Leitão, João; Pereira, José; Rodrigues, Luís

Gossip, or epidemic, protocols have emerged as a powerful strategy to implement highly scalable and resilient reliable broadcast primitives on large scale peer-to-peer networks. Epidemic protocols are scalable because they distribute the load among all nodes in the system and resilient because they have an intrinsic level of redundancy that masks node and network failures. This chapter provides an introduction to gossip-based broadcast on large-scale unstructured peer-to-peer overlay networks: it surveys the main results in the field, discusses techniques to build and maintain the overlays that support efficient dissemination strategies, and provides an in-depth discussion and experimental evaluation of two concrete protocols, named HyParView and Plumtree.

Exploring a QoS Driven Scheduling Approach for Peer-to-Peer Live Streaming Systems with Network Coding

PubMed Central

Cui, Laizhong; Lu, Nan; Chen, Fu

2014-01-01

Most large-scale peer-to-peer (P2P) live streaming systems use mesh to organize peers and leverage pull scheduling to transmit packets for providing robustness in dynamic environment. The pull scheduling brings large packet delay. Network coding makes the push scheduling feasible in mesh P2P live streaming and improves the efficiency. However, it may also introduce some extra delays and coding computational overhead. To improve the packet delay, streaming quality, and coding overhead, in this paper are as follows. we propose a QoS driven push scheduling approach. The main contributions of this paper are: (i) We introduce a new network coding method to increase the content diversity and reduce the complexity of scheduling; (ii) we formulate the push scheduling as an optimization problem and transform it to a min-cost flow problem for solving it in polynomial time; (iii) we propose a push scheduling algorithm to reduce the coding overhead and do extensive experiments to validate the effectiveness of our approach. Compared with previous approaches, the simulation results demonstrate that packet delay, continuity index, and coding ratio of our system can be significantly improved, especially in dynamic environments. PMID:25114968

[Clues to differentiate pregnancy-associated breast cancer from those diagnosed in postpartum period: A monocentric experience of pregnancy-associated cancer network (CALG)].

PubMed

Boudy, Anne-Sophie; Naoura, Iptissem; Zilberman, Sonia; Gligorov, Joseph; Chabbert-Buffet, Nathalie; Ballester, Marcos; Selleret, Lise; Darai, Emile

2017-06-01

To compare epidemiological, histological, therapeutic characteristics and prognosis of patients with breast cancer diagnosed during pregnancy with those diagnosed in postpartum period at a national expert center, « Cancer Associé à La Grossesse » network. Retrospective study of 108 patients with a pregnancy-associated breast cancer (PABC) between 2002 and 2016 comparing 51 patients with PABC during pregnancy and 57 patients with PABC of postpartum. Median gestational age at diagnosis was 16 weeks of gestation (WG). Median size (P=0.92), initial axillary pathology (P=0.29), histological type (P=0.33) and hormone receptor positive (P=0.93), were similar between groups. PABC during pregnancy overexpressed less frequently HER2 (12 % vs 36 %, P=0.003) and were less proliferant (Ki67≥15 %; 64 % vs 75 %, P=0.018) with less radical surgery (45 % vs 70 %, P=0.008). Sentinel lymph node biopsy was performed in 8 patients during pregnancy. Less patients of PABC during pregnancy received trastuzumab 12 % vs 37 %, P=0.003. Median delivery term was 37 WG. Median follow-up 3.2 vs 5.6 years (P=0.002) and recurrence rate for PABC during pregnancy and of postpartum were 3.2 vs 5.6 years (P=0.002) and 12 % vs 32 % (P=0.01), respectively. Our results emphasize histological, surgical and adjuvant treatment differences imposing differentiating PABC during pregnancy from those diagnosed in the postpartum period. Copyright © 2017 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

Scalable Management of Enterprise and Data-Center Networks

DTIC Science & Technology

2011-09-01

To the best of our knowledge , there is no systematic and efficient solution for handling overlapping wildcard rules in network-wide flow- management ...and D. Maltz, “Unraveling the complexity of network management ,” in NSDI, 2009. [4] P. Mahadevan, P. Sharma, S. Banerjee, and P. Ranganathan , “A...Scalable Management of Enterprise and Data-Center Networks Minlan Yu A Dissertation Presented to the Faculty of Princeton University in Candidacy for

Artificial intelligence modeling of cadmium(II) biosorption using rice straw

NASA Astrophysics Data System (ADS)

Nasr, Mahmoud; Mahmoud, Alaa El Din; Fawzy, Manal; Radwan, Ahmed

2017-05-01

The biosorption efficiency of Cd2+ using rice straw was investigated at room temperature (25 ± 4 °C), contact time (2 h) and agitation rate (5 Hz). Experiments studied the effect of three factors, biosorbent dose BD (0.1 and 0.5 g/L), pH (2 and 7) and initial Cd2+ concentration X (10 and 100 mg/L) at two levels "low" and "high". Results showed that, a variation in X from high to low revealed 31 % increase in the Cd2+ biosorption. However, a discrepancy in pH and BD from low to high achieved 28.60 and 23.61 % increase in the removal of Cd2+, respectively. From 23 factorial design, the effects of BD, pH and X achieved p value equals to 0.2248, 0.1881 and 0.1742, respectively, indicating that the influences are in the order X > pH > BD. Similarly, an adaptive neuro-fuzzy inference system indicated that X is the most influential with training and checking errors of 10.87 and 17.94, respectively. This trend was followed by "pH" with training error (15.80) and checking error (17.39), after that BD with training error (16.09) and checking error (16.29). A feed-forward back-propagation neural network with a configuration 3-6-1 achieved correlation ( R) of 0.99 (training), 0.82 (validation) and 0.97 (testing). Thus, the proposed network is capable of predicting Cd2+ biosorption with high accuracy, while the most significant variable was X.

77 FR 52337 - Eunice Kennedy Shriver National Institute of Child Health & Human Development Notice of Closed...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-29

... Institute of Child Health and Human Development Special Emphasis Panel; Contraceptive Clinical Trials Network (Male Studies) September. Date: September 27, 2012. Time: 2 p.m. to 4 p.m. Agenda: To review and...

A hybrid structured-unstructured grid method for unsteady turbomachinery flow computations

NASA Technical Reports Server (NTRS)

Mathur, Sanjay R.; Madavan, Nateri K.; Rajagopalan, R. G.

1993-01-01

A hybrid grid technique for the solution of 2D, unsteady flows is developed. This technique is capable of handling complex, multiple component geometries in relative motion, such as those encountered in turbomachinery. The numerical approach utilizes a mixed structured-unstructured zonal grid topology along with modeling equations and solution methods that are most appropriate in the individual domains, therefore combining the advantages of both structured and unstructured grid techniques.

Iron accumulation in deep brain nuclei in migraine: A population-based Magnetic Resonance Imaging study

PubMed Central

Kruit, Mark C.; Launer, Lenore J.; Overbosch, Jelle; van Buchem, Mark A.; Ferrari, Michel D.

2011-01-01

Background A small MRI study showed increased iron depositions in the periaqueductal grey matter in migraineurs, suggestive of a disturbed central antinociceptive neuronal network. Procedures With 1.5T MRI, we assessed iron concentrations in seven deep brain nuclei in a large population-based cohort. We compared T2 values between migraineurs (n=138) and controls (n=75), with multivariate regression analysis. Analyses were conducted in age strata (<50, n=112; ≥50) because iron measures are increasingly influenced by non-iron related factors in the older group. Findings Overall, migraineurs and controls did not differ, nor did migraineurs with vs. without aura. In the younger migraineurs compared to controls, T2-values were lower in the putamen (p=0.02), globus pallidus (p=0.03) and red nucleus (p=0.03). Similarly, in these younger migraineurs, controlling for age, those with longer migraine-history had lower T2 values in the putamen (p=0.01), caudate (p=0.04) and red nucleus (p=0.001). Conclusions Repeated migraine attacks are associated with increased iron concentration / accumulation in multiple deep nuclei that are involved in central pain processing and migraine pathophysiology. It remains unclear whether iron accumulation in the antinociceptive network has a causative role in the development of (chronic) migraine headache. PMID:19025553

Genome-wide mRNA and miRNA expression profiling reveal multiple regulatory networks in colorectal cancer

PubMed Central

Vishnubalaji, R; Hamam, R; Abdulla, M-H; Mohammed, M A V; Kassem, M; Al-Obeed, O; Aldahmash, A; Alajez, N M

2015-01-01

Despite recent advances in cancer management, colorectal cancer (CRC) remains the third most common cancer and a major health-care problem worldwide. MicroRNAs have recently emerged as key regulators of cancer development and progression by targeting multiple cancer-related genes; however, such regulatory networks are not well characterized in CRC. Thus, the aim of this study was to perform global messenger RNA (mRNA) and microRNA expression profiling in the same CRC samples and adjacent normal tissues and to identify potential miRNA-mRNA regulatory networks. Our data revealed 1273 significantly upregulated and 1902 downregulated genes in CRC. Pathway analysis revealed significant enrichment in cell cycle, integrated cancer, Wnt (wingless-type MMTV integration site family member), matrix metalloproteinase, and TGF-β pathways in CRC. Pharmacological inhibition of Wnt (using XAV939 or IWP-2) or TGF-β (using SB-431542) pathways led to dose- and time-dependent inhibition of CRC cell growth. Similarly, our data revealed up- (42) and downregulated (61) microRNAs in the same matched samples. Using target prediction and bioinformatics, ~77% of the upregulated genes were predicted to be targeted by microRNAs found to be downregulated in CRC. We subsequently focused on EZH2 (enhancer of zeste homolog 2 ), which was found to be regulated by hsa-miR-26a-5p and several members of the let-7 (lethal-7) family in CRC. Significant inverse correlation between EZH2 and hsa-miR-26a-5p (R2=0.56, P=0.0001) and hsa-let-7b-5p (R2=0.19, P=0.02) expression was observed in the same samples, corroborating the belief of EZH2 being a bona fide target for these two miRNAs in CRC. Pharmacological inhibition of EZH2 led to significant reduction in trimethylated histone H3 on lysine 27 (H3K27) methylation, marked reduction in cell proliferation, and migration in vitro. Concordantly, small interfering RNA-mediated knockdown of EZH2 led to similar effects on CRC cell growth in vitro. Therefore, our data have revealed several hundred potential miRNA-mRNA regulatory networks in CRC and suggest targeting relevant networks as potential therapeutic strategy for CRC. PMID:25611389

Genome-wide mRNA and miRNA expression profiling reveal multiple regulatory networks in colorectal cancer.

PubMed

Vishnubalaji, R; Hamam, R; Abdulla, M-H; Mohammed, M A V; Kassem, M; Al-Obeed, O; Aldahmash, A; Alajez, N M

2015-01-22

Despite recent advances in cancer management, colorectal cancer (CRC) remains the third most common cancer and a major health-care problem worldwide. MicroRNAs have recently emerged as key regulators of cancer development and progression by targeting multiple cancer-related genes; however, such regulatory networks are not well characterized in CRC. Thus, the aim of this study was to perform global messenger RNA (mRNA) and microRNA expression profiling in the same CRC samples and adjacent normal tissues and to identify potential miRNA-mRNA regulatory networks. Our data revealed 1273 significantly upregulated and 1902 downregulated genes in CRC. Pathway analysis revealed significant enrichment in cell cycle, integrated cancer, Wnt (wingless-type MMTV integration site family member), matrix metalloproteinase, and TGF-β pathways in CRC. Pharmacological inhibition of Wnt (using XAV939 or IWP-2) or TGF-β (using SB-431542) pathways led to dose- and time-dependent inhibition of CRC cell growth. Similarly, our data revealed up- (42) and downregulated (61) microRNAs in the same matched samples. Using target prediction and bioinformatics, ~77% of the upregulated genes were predicted to be targeted by microRNAs found to be downregulated in CRC. We subsequently focused on EZH2 (enhancer of zeste homolog 2 ), which was found to be regulated by hsa-miR-26a-5p and several members of the let-7 (lethal-7) family in CRC. Significant inverse correlation between EZH2 and hsa-miR-26a-5p (R(2)=0.56, P=0.0001) and hsa-let-7b-5p (R(2)=0.19, P=0.02) expression was observed in the same samples, corroborating the belief of EZH2 being a bona fide target for these two miRNAs in CRC. Pharmacological inhibition of EZH2 led to significant reduction in trimethylated histone H3 on lysine 27 (H3K27) methylation, marked reduction in cell proliferation, and migration in vitro. Concordantly, small interfering RNA-mediated knockdown of EZH2 led to similar effects on CRC cell growth in vitro. Therefore, our data have revealed several hundred potential miRNA-mRNA regulatory networks in CRC and suggest targeting relevant networks as potential therapeutic strategy for CRC.

Planning the City Logistics Terminal Location by Applying the Green p-Median Model and Type-2 Neurofuzzy Network

PubMed Central

Pamučar, Dragan; Vasin, Ljubislav; Atanasković, Predrag; Miličić, Milica

2016-01-01

The paper herein presents green p-median problem (GMP) which uses the adaptive type-2 neural network for the processing of environmental and sociological parameters including costs of logistics operators and demonstrates the influence of these parameters on planning the location for the city logistics terminal (CLT) within the discrete network. CLT shows direct effects on increment of traffic volume especially in urban areas, which further results in negative environmental effects such as air pollution and noise as well as increased number of urban populations suffering from bronchitis, asthma, and similar respiratory infections. By applying the green p-median model (GMM), negative effects on environment and health in urban areas caused by delivery vehicles may be reduced to minimum. This model creates real possibilities for making the proper investment decisions so as profitable investments may be realized in the field of transport infrastructure. The paper herein also includes testing of GMM in real conditions on four CLT locations in Belgrade City zone. PMID:27195005

Planning the City Logistics Terminal Location by Applying the Green p-Median Model and Type-2 Neurofuzzy Network.

PubMed

Pamučar, Dragan; Vasin, Ljubislav; Atanasković, Predrag; Miličić, Milica

2016-01-01

The paper herein presents green p-median problem (GMP) which uses the adaptive type-2 neural network for the processing of environmental and sociological parameters including costs of logistics operators and demonstrates the influence of these parameters on planning the location for the city logistics terminal (CLT) within the discrete network. CLT shows direct effects on increment of traffic volume especially in urban areas, which further results in negative environmental effects such as air pollution and noise as well as increased number of urban populations suffering from bronchitis, asthma, and similar respiratory infections. By applying the green p-median model (GMM), negative effects on environment and health in urban areas caused by delivery vehicles may be reduced to minimum. This model creates real possibilities for making the proper investment decisions so as profitable investments may be realized in the field of transport infrastructure. The paper herein also includes testing of GMM in real conditions on four CLT locations in Belgrade City zone.

Epidemic spreading in annealed directed networks: susceptible-infected-susceptible model and contact process.

PubMed

Kwon, Sungchul; Kim, Yup

2013-01-01

We investigate epidemic spreading in annealed directed scale-free networks with the in-degree (k) distribution P(in)(k)~k(-γ(in)) and the out-degree (ℓ) distribution, P(out)(ℓ)~ℓ(-γ(out)). The correlation of each node on the networks is controlled by the probability r(0≤r≤1) in two different algorithms, the so-called k and ℓ algorithms. For r=1, the k algorithm gives =, whereas the ℓ algorithm gives =<ℓ(2)>. For r=0, =<ℓ> for both algorithms. As the prototype of epidemic spreading, the susceptible-infected-susceptible model and contact process on the networks are analyzed using the heterogeneous mean-field theory and Monte Carlo simulations. The directedness of links and the correlation of the network are found to play important roles in the spreading, so that critical behaviors of both models are distinct from those on undirected scale-free networks.

Structure-composition trends in multicomponent borosilicate-based glasses deduced from molecular dynamics simulations with improved B-O and P-O force fields.

PubMed

Stevensson, Baltzar; Yu, Yang; Edén, Mattias

2018-03-28

We present a comprehensive molecular dynamics (MD) simulation study of composition-structure trends in a set of 25 glasses of widely spanning compositions from the following four systems of increasing complexity: Na 2 O-B 2 O 3 , Na 2 O-B 2 O 3 -SiO 2 , Na 2 O-CaO-SiO 2 -P 2 O 5 , and Na 2 O-CaO-B 2 O 3 -SiO 2 -P 2 O 5 . The simulations involved new B-O and P-O potential parameters developed within the polarizable shell-model framework, thereby combining the beneficial features of an overall high accuracy and excellent transferability among different glass systems and compositions: this was confirmed by the good accordance with experimental data on the relative BO 3 /BO 4 populations in borate and boro(phospho)silicate networks, as well as with the orthophosphate fractions in bioactive (boro)phosphosilicate glasses, which is believed to strongly influence their bone-bonding properties. The bearing of the simulated melt-cooling rate on the borate/phosphate speciations is discussed. Each local {BO 3 , BO 4 , SiO 4 , PO 4 } coordination environment remained independent of the precise set of co-existing network formers, while all trends observed in bond-lengths/angles mainly reflected the glass-network polymerization, i.e., the relative amounts of bridging oxygen (BO) and non-bridging oxygen (NBO) species. The structural roles of the Na + /Ca 2+ cations were also probed, targeting their local coordination environments and their relative preferences to associate with the various borate, silicate, and phosphate moieties. We evaluate and discuss the common classification of alkali/alkaline-earth metal ions as charge-compensators of either BO 4 tetrahedra or NBO anions in borosilicate glasses, also encompassing the less explored NBO-rich regime: the Na + /Ca 2+ cations mainly associate with BO/NBO species of SiO 4 /BO 3 groups, with significant relative Na-BO 4 contacts only observed in B-rich glass networks devoid of NBO species, whereas NBO-rich glass networks also reveal substantial amounts of NBO-bearing BO 4 tetrahedra.

Molecular dynamics simulation of phosphorylated KID post-translational modification.

PubMed

Chen, Hai-Feng

2009-08-05

Kinase-inducible domain (KID) as transcriptional activator can stimulate target gene expression in signal transduction by associating with KID interacting domain (KIX). NMR spectra suggest that apo-KID is an unstructured protein. After post-translational modification by phosphorylation, KID undergoes a transition from disordered to well folded protein upon binding to KIX. However, the mechanism of folding coupled to binding is poorly understood. To get an insight into the mechanism, we have performed ten trajectories of explicit-solvent molecular dynamics (MD) for both bound and apo phosphorylated KID (pKID). Ten MD simulations are sufficient to capture the average properties in the protein folding and unfolding. Room-temperature MD simulations suggest that pKID becomes more rigid and stable upon the KIX-binding. Kinetic analysis of high-temperature MD simulations shows that bound pKID and apo-pKID unfold via a three-state and a two-state process, respectively. Both kinetics and free energy landscape analyses indicate that bound pKID folds in the order of KIX access, initiation of pKID tertiary folding, folding of helix alpha(B), folding of helix alpha(A), completion of pKID tertiary folding, and finalization of pKID-KIX binding. Our data show that the folding pathways of apo-pKID are different from the bound state: the foldings of helices alpha(A) and alpha(B) are swapped. Here we also show that Asn139, Asp140 and Leu141 with large Phi-values are key residues in the folding of bound pKID. Our results are in good agreement with NMR experimental observations and provide significant insight into the general mechanisms of binding induced protein folding and other conformational adjustment in post-translational modification.

Lymphatic microangiopathy of the skin in systemic sclerosis.

PubMed

Leu, A J; Gretener, S B; Enderlin, S; Brühlmann, P; Michel, B A; Kowal-Bielecka, O; Hoffmann, U; Franzeck, U K

1999-03-01

The cutaneous capillary lymphatic system in patients with systemic sclerosis was investigated using fluorescence microlymphography. The distal upper limbs of 16 healthy controls (mean age 62.3+/-13.1 yr) and 16 patients with systemic sclerosis (mean age 58.9+/-13.6 yr) were examined and the following parameters were evaluated: (a) single lymphatic capillaries; (b) lymphatic capillary network and cutaneous backflow; (c) extension of the stained lymphatics; (d) diameter of single lymphatic capillaries. At the finger level, lymphatic capillaries were lacking in five patients, while they were present in all controls (P < 0.05). Extension of the stained lymphatics was increased in 11 patients (8.1+/-6.0 mm) compared to the 16 healthy controls (2.0+/-1.2 mm) (P < 0.0001). Cutaneous backflow was observed in three patients (P < 0.05). At the hand level, lymphatic network extension was significantly different between patients (3.8+/-2.4 mm) and controls (1.2+/-0.8 mm) (P < 0.01); however, no significant differences were found at the forearm level. Lesional skin in patients with systemic sclerosis exhibits evidence of lymphatic microangiopathy.

Exploring the Therapeutic Mechanism of Desmodium styracifolium on Oxalate Crystal-Induced Kidney Injuries Using Comprehensive Approaches Based on Proteomics and Network Pharmacology.

PubMed

Hou, Jiebin; Chen, Wei; Lu, Hongtao; Zhao, Hongxia; Gao, Songyan; Liu, Wenrui; Dong, Xin; Guo, Zhiyong

2018-01-01

Purpose: As a Chinese medicinal herb, Desmodium styracifolium (Osb.) Merr (DS) has been applied clinically to alleviate crystal-induced kidney injuries, but its effective components and their specific mechanisms still need further exploration. This research first combined the methods of network pharmacology and proteomics to explore the therapeutic protein targets of DS on oxalate crystal-induced kidney injuries to provide a reference for relevant clinical use. Methods: Oxalate-induced kidney injury mouse, rat, and HK-2 cell models were established. Proteins differentially expressed between the oxalate and control groups were respectively screened using iTRAQ combined with MALDI-TOF-MS. The common differential proteins of the three models were further analyzed by molecular docking with DS compounds to acquire differential targets. The inverse docking targets of DS were predicted through the platform of PharmMapper. The protein-protein interaction (PPI) relationship between the inverse docking targets and the differential proteins was established by STRING. Potential targets were further validated by western blot based on a mouse model with DS treatment. The effects of constituent compounds, including luteolin, apigenin, and genistein, were investigated based on an oxalate-stimulated HK-2 cell model. Results: Thirty-six common differentially expressed proteins were identified by proteomic analysis. According to previous research, the 3D structures of 15 major constituents of DS were acquired. Nineteen differential targets, including cathepsin D (CTSD), were found using molecular docking, and the component-differential target network was established. Inverse-docking targets including p38 MAPK and CDK-2 were found, and the network of component-reverse docking target was established. Through PPI analysis, 17 inverse-docking targets were linked to differential proteins. The combined network of component-inverse docking target-differential proteins was then constructed. The expressions of CTSD, p-p38 MAPK, and p-CDK-2 were shown to be increased in the oxalate group and decreased in kidney tissue by the DS treatment. Luteolin, apigenin, and genistein could protect oxalate-stimulated tubular cells as active components of DS. Conclusion: The potential targets including the CTSD, p38 MAPK, and CDK2 of DS in oxalate-induced kidney injuries and the active components (luteolin, apigenin, and genistein) of DS were successfully identified in this study by combining proteomics analysis, network pharmacology prediction, and experimental validation.

Selective Activation of Sphingosine 1-Phosphate Receptors 1 and 3 Promotes Local Microvascular Network Growth

PubMed Central

Sefcik, Lauren S.; Petrie Aronin, Caren E.; Awojoodu, Anthony O.; Shin, Soo J.; Mac Gabhann, Feilim; MacDonald, Timothy L.; Wamhoff, Brian R.; Lynch, Kevin R.; Peirce, Shayn M.

2011-01-01

Proper spatial and temporal regulation of microvascular remodeling is critical to the formation of functional vascular networks, spanning the various arterial, venous, capillary, and collateral vessel systems. Recently, our group has demonstrated that sustained release of sphingosine 1-phosphate (S1P) from biodegradable polymers promotes microvascular network growth and arteriolar expansion. In this study, we employed S1P receptor-specific compounds to activate and antagonize different combinations of S1P receptors to elucidate those receptors most critical for promotion of pharmacologically induced microvascular network growth. We show that S1P1 and S1P3 receptors act synergistically to enhance functional network formation via increased functional length density, arteriolar diameter expansion, and increased vascular branching in the dorsal skinfold window chamber model. FTY720, a potent activator of S1P1 and S1P3, promoted a 107% and 153% increase in length density 3 and 7 days after implantation, respectively. It also increased arteriolar diameters by 60% and 85% 3 and 7 days after implantation. FTY720-stimulated branching in venules significantly more than unloaded poly(D, L-lactic-co-glycolic acid). When implanted on the mouse spinotrapezius muscle, FTY720 stimulated an arteriogenic response characterized by increased tortuosity and collateralization of branching microvascular networks. Our results demonstrate the effectiveness of S1P1 and S1P3 receptor-selective agonists (such as FTY720) in promoting microvascular growth for tissue engineering applications. PMID:20874260

Impaired cerebral blood flow networks in temporal lobe epilepsy with hippocampal sclerosis: A graph theoretical approach.

PubMed

Sone, Daichi; Matsuda, Hiroshi; Ota, Miho; Maikusa, Norihide; Kimura, Yukio; Sumida, Kaoru; Yokoyama, Kota; Imabayashi, Etsuko; Watanabe, Masako; Watanabe, Yutaka; Okazaki, Mitsutoshi; Sato, Noriko

2016-09-01

Graph theory is an emerging method to investigate brain networks. Altered cerebral blood flow (CBF) has frequently been reported in temporal lobe epilepsy (TLE), but graph theoretical findings of CBF are poorly understood. Here, we explored graph theoretical networks of CBF in TLE using arterial spin labeling imaging. We recruited patients with TLE and unilateral hippocampal sclerosis (HS) (19 patients with left TLE, and 21 with right TLE) and 20 gender- and age-matched healthy control subjects. We obtained all participants' CBF maps using pseudo-continuous arterial spin labeling and analyzed them using the Graph Analysis Toolbox (GAT) software program. As a result, compared to the controls, the patients with left TLE showed a significantly low clustering coefficient (p=0.024), local efficiency (p=0.001), global efficiency (p=0.010), and high transitivity (p=0.015), whereas the patients with right TLE showed significantly high assortativity (p=0.046) and transitivity (p=0.011). The group with right TLE also had high characteristic path length values (p=0.085), low global efficiency (p=0.078), and low resilience to targeted attack (p=0.101) at a trend level. Lower normalized clustering coefficient (p=0.081) in the left TLE and higher normalized characteristic path length (p=0.089) in the right TLE were found also at a trend level. Both the patients with left and right TLE showed significantly decreased clustering in similar areas, i.e., the cingulate gyri, precuneus, and occipital lobe. Our findings revealed differing left-right network metrics in which an inefficient CBF network in left TLE and vulnerability to irritation in right TLE are suggested. The left-right common finding of regional decreased clustering might reflect impaired default-mode networks in TLE. Copyright © 2016 Elsevier Inc. All rights reserved.

In-situ immobilization of quantum dots in polysaccharide-based nanogels for integration of optical pH-sensing, tumor cell imaging, and drug delivery.

PubMed

Wu, Weitai; Aiello, Michael; Zhou, Ting; Berliner, Alexandra; Banerjee, Probal; Zhou, Shuiqin

2010-04-01

We report a class of polysaccharide-based hybrid nanogels that can integrate the functional building blocks for optical pH-sensing, cancer cell imaging, and controlled drug release into a single nanoparticle system, which can offer broad opportunities for combined diagnosis and therapy. The hybrid nanogels were prepared by in-situ immobilization of CdSe quantum dots (QDs) in the interior of the pH and temperature dual responsive hydroxypropylcellulose-poly(acrylic acid) (HPC-PAA) semi-interpenetrating polymer networks. The-OH groups of the HPC chains are designed to sequester the precursor Cd(2+) ions into the nanogels as well as stabilize the in-situ formed CdSe QDs. The pH-sensitive PAA network chains are designed to induce a pH-responsive volume phase transition of the hybrid nanogels. The developed HPC-PAA-CdSe hybrid nanogels combine a strong trap emission at 741nm for sensing physicochemical environment in a pH dependent manner and a visible excitonic emission at 592nm for mouse melanoma B16F10 cell imaging. The hybrid nanogels also provide excellent stability as a drug carrier, which cannot only provide a high drug loading capacity for a model anticancer drug temozolomide, but also offer a pH-triggered sustained-release of the drug molecules in the gel network. Copyright 2010 Elsevier Ltd. All rights reserved.

Characterization and preparation of p(U-MMA-An) interpenetrating polymer network damping and absorbing material.

PubMed

Liu, Jun; Li, Qingshan; Zhuo, Yuguo; Hong, Wei; Lv, Wenfeng; Xing, Guangzhong

2014-06-01

P(U-MMA-ANI) interpenetrating polymer network (IPN) damping and absorbing material is successfully synthesized by PANI particles served as an absorbing agent with the microemulsion polymerization and P(U-MMA) foam IPN network structure for substrate materials with foaming way. P(U-MMA-ANI) IPN is characterized by the compression mechanical performance testing, TG-DSC, and DSC. The results verify that the P(U-MMA) IPN foam damping material has a good compressive strength and compaction cycle property, and the optimum content of PMMA was 40% (mass) with which the SEM graphs do not present the phase separation on the macro level between PMMA and PU, while the phase separation was observed on the micro level. The DTG curve indicates that because of the formation of P(U-MMA) IPN, the decomposition temperature of PMMA and the carbamate in PU increases, while that of the polyol segment in PU has almost no change. P(U-MMA-ANI) IPN foam damping and absorbing material is obtained by PANI particles served as absorbing agent in the form of filler, and PMMA in the form of micro area in substrate material. When the content of PANI was up to 2.0% (mass), the dissipation factor of composites increased, and with the increasing of frequency the dissipation factor increased in a straight line.

Relationships between the resting-state network and the P3: Evidence from a scalp EEG study

NASA Astrophysics Data System (ADS)

Li, Fali; Liu, Tiejun; Wang, Fei; Li, He; Gong, Diankun; Zhang, Rui; Jiang, Yi; Tian, Yin; Guo, Daqing; Yao, Dezhong; Xu, Peng

2015-10-01

The P3 is an important event-related potential that can be used to identify neural activity related to the cognitive processes of the human brain. However, the relationships, especially the functional correlations, between resting-state brain activity and the P3 have not been well established. In this study, we investigated the relationships between P3 properties (i.e., amplitude and latency) and resting-state brain networks. The results indicated that P3 amplitude was significantly correlated with resting-state network topology, and in general, larger P3 amplitudes could be evoked when the resting-state brain network was more efficient. However, no significant relationships were found for the corresponding P3 latency. Additionally, the long-range connections between the prefrontal/frontal and parietal/occipital brain regions, which represent the synchronous activity of these areas, were functionally related to the P3 parameters, especially P3 amplitude. The findings of the current study may help us better understand inter-subject variation in the P3, which may be instructive for clinical diagnosis, cognitive neuroscience studies, and potential subject selection for brain-computer interface applications.

Transcriptional Consequences of 16p11.2 Deletion and Duplication in Mouse Cortex and Multiplex Autism Families

PubMed Central

Blumenthal, Ian; Ragavendran, Ashok; Erdin, Serkan; Klei, Lambertus; Sugathan, Aarathi; Guide, Jolene R.; Manavalan, Poornima; Zhou, Julian Q.; Wheeler, Vanessa C.; Levin, Joshua Z.; Ernst, Carl; Roeder, Kathryn; Devlin, Bernie; Gusella, James F.; Talkowski, Michael E.

2014-01-01

Reciprocal copy-number variation (CNV) of a 593 kb region of 16p11.2 is a common genetic cause of autism spectrum disorder (ASD), yet it is not completely penetrant and can manifest in a wide array of phenotypes. To explore its molecular consequences, we performed RNA sequencing of cerebral cortex from mouse models with CNV of the syntenic 7qF3 region and lymphoblast lines from 34 members of 7 multiplex ASD-affected families harboring the 16p11.2 CNV. Expression of all genes in the CNV region correlated well with their DNA copy number, with no evidence of dosage compensation. We observed effects on gene expression outside the CNV region, including apparent positional effects in cis and in trans at genomic segments with evidence of physical interaction in Hi-C chromosome conformation data. One of the most significant positional effects was telomeric to the 16p11.2 CNV and includes the previously described “distal” 16p11.2 microdeletion. Overall, 16p11.2 CNV was associated with altered expression of genes and networks that converge on multiple hypotheses of ASD pathogenesis, including synaptic function (e.g., NRXN1, NRXN3), chromatin modification (e.g., CHD8, EHMT1, MECP2), transcriptional regulation (e.g., TCF4, SATB2), and intellectual disability (e.g., FMR1, CEP290). However, there were differences between tissues and species, with the strongest effects being consistently within the CNV region itself. Our analyses suggest that through a combination of indirect regulatory effects and direct effects on nuclear architecture, alteration of 16p11.2 genes disrupts expression networks that involve other genes and pathways known to contribute to ASD, suggesting an overlap in mechanisms of pathogenesis. PMID:24906019

A Risk Stratification Model for Lung Cancer Based on Gene Coexpression Network and Deep Learning

PubMed Central

2018-01-01

Risk stratification model for lung cancer with gene expression profile is of great interest. Instead of previous models based on individual prognostic genes, we aimed to develop a novel system-level risk stratification model for lung adenocarcinoma based on gene coexpression network. Using multiple microarray, gene coexpression network analysis was performed to identify survival-related networks. A deep learning based risk stratification model was constructed with representative genes of these networks. The model was validated in two test sets. Survival analysis was performed using the output of the model to evaluate whether it could predict patients' survival independent of clinicopathological variables. Five networks were significantly associated with patients' survival. Considering prognostic significance and representativeness, genes of the two survival-related networks were selected for input of the model. The output of the model was significantly associated with patients' survival in two test sets and training set (p < 0.00001, p < 0.0001 and p = 0.02 for training and test sets 1 and 2, resp.). In multivariate analyses, the model was associated with patients' prognosis independent of other clinicopathological features. Our study presents a new perspective on incorporating gene coexpression networks into the gene expression signature and clinical application of deep learning in genomic data science for prognosis prediction. PMID:29581968

Yeast prion architecture explains how proteins can be genes

NASA Astrophysics Data System (ADS)

Wickner, Reed

2013-03-01

Prions (infectious proteins) transmit information without an accompanying DNA or RNA. Most yeast prions are self-propagating amyloids that inactivate a normally functional protein. A single protein can become any of several prion variants, with different manifestations due to different amyloid structures. We showed that the yeast prion amyloids of Ure2p, Sup35p and Rnq1p are folded in-register parallel beta sheets using solid state NMR dipolar recoupling experiments, mass-per-filament-length measurements, and filament diameter measurements. The extent of beta sheet structure, measured by chemical shifts in solid-state NMR and acquired protease-resistance on amyloid formation, combined with the measured filament diameters, imply that the beta sheets must be folded along the long axis of the filament. We speculate that prion variants of a single protein sequence differ in the location of these folds. Favorable interactions between identical side chains must hold these structures in-register. The same interactions must guide an unstructured monomer joining the end of a filament to assume the same conformation as molecules already in the filament, with the turns at the same locations. In this way, a protein can template its own conformation, in analogy to the ability of a DNA molecule to template its sequence by specific base-pairing. Bldg. 8, Room 225, NIH, 8 Center Drive MSC 0830, Bethesda, MD 20892-0830, wickner@helix.nih.gov, 301-496-3452

catena-Poly[[triphenyl-tin(IV)]-μ-phenyl-phosphinato-κO:O'].

PubMed

Diop, Tidiane; Diop, Libasse; Kociok-Köhn, Gabriele; Molloy, Kieran C; Stoeckli-Evans, Helen

2011-12-01

In the structure of the title coordination polymer, [Sn(C(6)H(5))(3)(C(6)H(6)O(2)P)](n) or [PhP(H)O(2)Sn(IV)(Ph)(3)](n), the Sn(IV) atom is five-coordinate, with the SnC(3)O(2) framework in a trans trigonal-bipyramidal arrangement having the PhP(H)O(2) (-) anions in apical positions. In the crystal, neighbouring polymer chains are linked via C-H⋯π inter-actions, forming a two-dimensional network lying parallel to (001).

Brain networks associated with cognitive and hedonic responses to a meal.

PubMed

Pribic, T; Kilpatrick, L; Ciccantelli, B; Malagelada, C; Accarino, A; Rovira, A; Pareto, D; Mayer, E; Azpiroz, F

2017-06-01

We recently reported interrelated digestive, cognitive, and hedonic responses to a meal. The aim of this study was to identify brain networks related to the hedonic response to eating. Thirty-eight healthy subjects (20-38 age range) were evaluated after a 5-hour fast and after ingestion of a test meal (juice and warm ham and cheese sandwich, 300 mL, 425 kcal). Perceptual and affective responses (satiety, abdominal fullness, digestive well-being, and positive mood), and resting scans of the brain using functional MRI (3T Trio, Siemens, Germany) were evaluated immediately before and after the test meal. A high-order group independent component analysis was performed to investigate ingestion-related changes in the intrinsic connectivity of brain networks, with a focus on thalamic and insular networks. Ingestion induced satiation (3.3±0.4 score increase; P<.001) and abdominal fullness (2.4±0.3 score increase; P<.001). These sensations included an affective dimension involving digestive well-being (2.8±0.3 score increase; P<.001) and positive mood (1.8±0.2 score increase; P<.001). In general, thalamo-cortical connectivity increased with meal ingestion while insular-cortical connectivity mainly decreased. Furthermore, larger meal-induced changes (increase/decrease) in specific thalamic connections were associated with smaller changes in satiety/fullness. In contrast, a larger meal-induced decrease in insular-anterior cingulate cortex connectivity was associated with increased satiety, fullness, and digestive well-being. Perceptual and emotional responses to food intake are related to brain connectivity in defined functional networks. Brain imaging may provide objective biomarkers of subjective effects of meal ingestion. © 2017 John Wiley & Sons Ltd.

Influence of parameter values on the oscillation sensitivities of two p53-Mdm2 models.

PubMed

Cuba, Christian E; Valle, Alexander R; Ayala-Charca, Giancarlo; Villota, Elizabeth R; Coronado, Alberto M

2015-09-01

Biomolecular networks that present oscillatory behavior are ubiquitous in nature. While some design principles for robust oscillations have been identified, it is not well understood how these oscillations are affected when the kinetic parameters are constantly changing or are not precisely known, as often occurs in cellular environments. Many models of diverse complexity level, for systems such as circadian rhythms, cell cycle or the p53 network, have been proposed. Here we assess the influence of hundreds of different parameter sets on the sensitivities of two configurations of a well-known oscillatory system, the p53 core network. We show that, for both models and all parameter sets, the parameter related to the p53 positive feedback, i.e. self-promotion, is the only one that presents sizeable sensitivities on extrema, periods and delay. Moreover, varying the parameter set values to change the dynamical characteristics of the response is more restricted in the simple model, whereas the complex model shows greater tunability. These results highlight the importance of the presence of specific network patterns, in addition to the role of parameter values, when we want to characterize oscillatory biochemical systems.

In Vivo Intracellular pH Measurements in Tobacco and Arabidopsis Reveal an Unexpected pH Gradient in the Endomembrane System[W

PubMed Central

Martinière, Alexandre; Bassil, Elias; Jublanc, Elodie; Alcon, Carine; Reguera, Maria; Sentenac, Hervé; Blumwald, Eduardo; Paris, Nadine

2013-01-01

The pH homeostasis of endomembranes is essential for cellular functions. In order to provide direct pH measurements in the endomembrane system lumen, we targeted genetically encoded ratiometric pH sensors to the cytosol, the endoplasmic reticulum, and the trans-Golgi, or the compartments labeled by the vacuolar sorting receptor (VSR), which includes the trans-Golgi network and prevacuoles. Using noninvasive live-cell imaging to measure pH, we show that a gradual acidification from the endoplasmic reticulum to the lytic vacuole exists, in both tobacco (Nicotiana tabacum) epidermal (ΔpH −1.5) and Arabidopsis thaliana root cells (ΔpH −2.1). The average pH in VSR compartments was intermediate between that of the trans-Golgi and the vacuole. Combining pH measurements with in vivo colocalization experiments, we found that the trans-Golgi network had an acidic pH of 6.1, while the prevacuole and late prevacuole were both more alkaline, with pH of 6.6 and 7.1, respectively. We also showed that endosomal pH, and subsequently vacuolar trafficking of soluble proteins, requires both vacuolar-type H+ ATPase–dependent acidification as well as proton efflux mediated at least by the activity of endosomal sodium/proton NHX-type antiporters. PMID:24104564

Graph theoretical analysis of functional network for comprehension of sign language.

PubMed

Liu, Lanfang; Yan, Xin; Liu, Jin; Xia, Mingrui; Lu, Chunming; Emmorey, Karen; Chu, Mingyuan; Ding, Guosheng

2017-09-15

Signed languages are natural human languages using the visual-motor modality. Previous neuroimaging studies based on univariate activation analysis show that a widely overlapped cortical network is recruited regardless whether the sign language is comprehended (for signers) or not (for non-signers). Here we move beyond previous studies by examining whether the functional connectivity profiles and the underlying organizational structure of the overlapped neural network may differ between signers and non-signers when watching sign language. Using graph theoretical analysis (GTA) and fMRI, we compared the large-scale functional network organization in hearing signers with non-signers during the observation of sentences in Chinese Sign Language. We found that signed sentences elicited highly similar cortical activations in the two groups of participants, with slightly larger responses within the left frontal and left temporal gyrus in signers than in non-signers. Crucially, further GTA revealed substantial group differences in the topologies of this activation network. Globally, the network engaged by signers showed higher local efficiency (t (24) =2.379, p=0.026), small-worldness (t (24) =2.604, p=0.016) and modularity (t (24) =3.513, p=0.002), and exhibited different modular structures, compared to the network engaged by non-signers. Locally, the left ventral pars opercularis served as a network hub in the signer group but not in the non-signer group. These findings suggest that, despite overlap in cortical activation, the neural substrates underlying sign language comprehension are distinguishable at the network level from those for the processing of gestural action. Copyright © 2017 Elsevier B.V. All rights reserved.

All Source Sensor Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

- PNNL, Harold Trease

2012-10-10

ASSA is a software application that processes binary data into summarized index tables that can be used to organize features contained within the data. ASSA's index tables can also be used to search for user specified features. ASSA is designed to organize and search for patterns in unstructured binary data streams or archives, such as video, images, audio, and network traffic. ASSA is basically a very general search engine used to search for any pattern in any binary data stream. It has uses in video analytics, image analysis, audio analysis, searching hard-drives, monitoring network traffic, etc.

A network model framework for prioritizing wetland conservation in the Great Plains

USGS Publications Warehouse

Albanese, Gene; Haukos, David A.

2017-01-01

ContextPlaya wetlands are the primary habitat for numerous wetland-dependent species in the Southern Great Plains of North America. Plant and wildlife populations that inhabit these wetlands are reciprocally linked through the dispersal of individuals, propagules and ultimately genes among local populations.ObjectiveTo develop and implement a framework using network models for conceptualizing, representing and analyzing potential biological flows among 48,981 spatially discrete playa wetlands in the Southern Great Plains.MethodsWe examined changes in connectivity patterns and assessed the relative importance of wetlands to maintaining these patterns by targeting wetlands for removal based on network centrality metrics weighted by estimates of habitat quality and probability of inundation.ResultsWe identified several distinct, broad-scale sub networks and phase transitions among playa wetlands in the Southern Plains. In particular, for organisms that can disperse >2 km a dense and expansive wetland sub network emerges in the Southern High Plains. This network was characterized by localized, densely connected wetland clusters at link distances (h) >2 km but <5 km and was most sensitive to changes in wetland availability (p) and configuration when h = 4 km, and p = 0.2–0.4. It transitioned to a single, large connected wetland system at broader spatial scales even when the proportion of inundated wetland was relatively low (p = 0.2).ConclusionsOur findings suggest that redundancy in the potential for broad and fine-scale movements insulates this system from damage and facilitates system-wide connectivity among populations with different dispersal capacities.

Prediction of heat capacity of amine solutions using artificial neural network and thermodynamic models for CO2 capture processes

NASA Astrophysics Data System (ADS)

Afkhamipour, Morteza; Mofarahi, Masoud; Borhani, Tohid Nejad Ghaffar; Zanganeh, Masoud

2018-03-01

In this study, artificial neural network (ANN) and thermodynamic models were developed for prediction of the heat capacity ( C P ) of amine-based solvents. For ANN model, independent variables such as concentration, temperature, molecular weight and CO2 loading of amine were selected as the inputs of the model. The significance of the input variables of the ANN model on the C P values was investigated statistically by analyzing of correlation matrix. A thermodynamic model based on the Redlich-Kister equation was used to correlate the excess molar heat capacity ({C}_P^E) data as function of temperature. In addition, the effects of temperature and CO2 loading at different concentrations of conventional amines on the C P values were investigated. Both models were validated against experimental data and very good results were obtained between two mentioned models and experimental data of C P collected from various literatures. The AARD between ANN model results and experimental data of C P for 47 systems of amine-based solvents studied was 4.3%. For conventional amines, the AARD for ANN model and thermodynamic model in comparison with experimental data were 0.59% and 0.57%, respectively. The results showed that both ANN and Redlich-Kister models can be used as a practical tool for simulation and designing of CO2 removal processes by using amine solutions.

Pathways for Emotions: Specializations in the Amygdalar, Mediodorsal Thalamic, and Posterior Orbitofrontal Network.

PubMed

Timbie, Clare; Barbas, Helen

2015-08-26

The primate amygdala projects to posterior orbitofrontal cortex (pOFC) directly and possibly indirectly through a pathway to the magnocellular mediodorsal thalamic nucleus (MDmc), which may convey signals about the significance of stimuli. However, because MDmc receives input from structures in addition to the amygdala and MDmc projects to areas in addition to pOFC, it is unknown whether amygdalar pathways in MDmc innervate pOFC-bound neurons. We addressed this issue using double- or triple-labeling approaches to identify pathways and key cellular and molecular features in rhesus monkeys. We found that amygdalar terminations innervated labeled neurons in MDmc that project to pOFC. Projection neurons in MDmc directed to pOFC included comparatively fewer "core" parvalbumin neurons that project focally to the middle cortical layers and more "matrix" calbindin neurons that project expansively to the upper cortical layers. In addition, a small and hitherto unknown pathway originated from MDmc calretinin neurons and projected to pOFC. Further, whereas projection neurons directed to MDmc and to pOFC were intermingled in the amygdala, none projected to both structures. Larger amygdalar neurons projected to MDmc and expressed the vesicular glutamate transporter 2 (VGLUT2), which is found in highly efficient "driver" pathways. In contrast, smaller amygdalar neurons directed to pOFC expressed VGLUT1 found in modulatory pathways. The indirect pathway from the amygdala to pOFC via MDmc may provide information about the emotional significance of events and, along with a parallel direct pathway, ensures transfer of signals to all layers of pOFC. The amygdala-the brain's center for emotions-is strongly linked with the orbital cortex, a region associated with social interactions. This study provides evidence that a robust pathway from the amygdala reaches neurons in the thalamus that link directly with the orbital cortex, forming a tight tripartite network. The dual pathways from the amygdala to the orbital cortex and to the thalamus are distinct by morphology, neurochemistry, and function. This tightly linked network suggests the presence of fool-proof avenues for emotions to influence high-order cortical areas associated with affective reasoning. Specific nodes of this tripartite network are disrupted in psychiatric diseases, divorcing areas that integrate emotions and thoughts for decisions and flexible behavior. Copyright © 2015 the authors 0270-6474/15/3511976-12$15.00/0.

Youth, new media, and HIV/AIDS: determinants of participation in an online health social movement.

PubMed

Vijaykumar, Santosh; Wray, Ricardo J; Buskirk, Trent; Piplani, Himakshi; Banerjee, Joya; Furdyk, Michael; Pattni, Reshma

2014-07-01

Abstract This paper focuses on the Global Youth Coalition for HIV/AIDS (GYCA), a collaboration of young people who utilize the Internet to organize and inform the global youth HIV/AIDS social movement. We used a trans-disciplinary conceptual framework guided by the diffusion of innovations approach to explore factors that influence online participation among the coalition's members and to explain perceived effects of participation. We used a randomized stratified sampling strategy to conduct an online 7 week survey of GYCA's members (n=275). Descriptive statistics revealed that the majority of participants were from Africa (∼54%) and Asia (∼24%), with an average age of 27 years. Multiple linear regression analyses showed that participation in the e-consultations (R(2)=0.39, p<0.001) was influenced by a greater number of factors compared to the listserv (R(2)=0.20, p<0.001). Online participation significantly influenced perceptions about the coalition's social networking utility (R(2)=0.21, p<0.001). Perceived social networking utility significantly explained perceived effects on program areas such as knowledge sharing (R(2)=0.49, p<0.001), capacity building (R(2)=0.48, p<0.001), and political advocacy (R(2)=0.44, p<0.001). We concluded that a range of factors shapes participation in online health social movements. Initiatives such as GYCA need regular, intensive assessments to understand these factors for better tailoring their online activities to members' needs and for greater impact.

Discretized kinetic theory on scale-free networks

NASA Astrophysics Data System (ADS)

Bertotti, Maria Letizia; Modanese, Giovanni

2016-10-01

The network of interpersonal connections is one of the possible heterogeneous factors which affect the income distribution emerging from micro-to-macro economic models. In this paper we equip our model discussed in [1, 2] with a network structure. The model is based on a system of n differential equations of the kinetic discretized-Boltzmann kind. The network structure is incorporated in a probabilistic way, through the introduction of a link density P(α) and of correlation coefficients P(β|α), which give the conditioned probability that an individual with α links is connected to one with β links. We study the properties of the equations and give analytical results concerning the existence, normalization and positivity of the solutions. For a fixed network with P(α) = c/α q , we investigate numerically the dependence of the detailed and marginal equilibrium distributions on the initial conditions and on the exponent q. Our results are compatible with those obtained from the Bouchaud-Mezard model and from agent-based simulations, and provide additional information about the dependence of the individual income on the level of connectivity.

Overcoming the Challenges of Unstructured Data in Multisite, Electronic Medical Record-based Abstraction.

PubMed

Polnaszek, Brock; Gilmore-Bykovskyi, Andrea; Hovanes, Melissa; Roiland, Rachel; Ferguson, Patrick; Brown, Roger; Kind, Amy J H

2016-10-01

Unstructured data encountered during retrospective electronic medical record (EMR) abstraction has routinely been identified as challenging to reliably abstract, as these data are often recorded as free text, without limitations to format or structure. There is increased interest in reliably abstracting this type of data given its prominent role in care coordination and communication, yet limited methodological guidance exists. As standard abstraction approaches resulted in substandard data reliability for unstructured data elements collected as part of a multisite, retrospective EMR study of hospital discharge communication quality, our goal was to develop, apply and examine the utility of a phase-based approach to reliably abstract unstructured data. This approach is examined using the specific example of discharge communication for warfarin management. We adopted a "fit-for-use" framework to guide the development and evaluation of abstraction methods using a 4-step, phase-based approach including (1) team building; (2) identification of challenges; (3) adaptation of abstraction methods; and (4) systematic data quality monitoring. Unstructured data elements were the focus of this study, including elements communicating steps in warfarin management (eg, warfarin initiation) and medical follow-up (eg, timeframe for follow-up). After implementation of the phase-based approach, interrater reliability for all unstructured data elements demonstrated κ's of ≥0.89-an average increase of +0.25 for each unstructured data element. As compared with standard abstraction methodologies, this phase-based approach was more time intensive, but did markedly increase abstraction reliability for unstructured data elements within multisite EMR documentation.

Relay discovery and selection for large-scale P2P streaming

PubMed Central

Zhang, Chengwei; Wang, Angela Yunxian

2017-01-01

In peer-to-peer networks, application relays have been commonly used to provide various networking services. The service performance often improves significantly if a relay is selected appropriately based on its network location. In this paper, we studied the location-aware relay discovery and selection problem for large-scale P2P streaming networks. In these large-scale and dynamic overlays, it incurs significant communication and computation cost to discover a sufficiently large relay candidate set and further to select one relay with good performance. The network location can be measured directly or indirectly with the tradeoffs between timeliness, overhead and accuracy. Based on a measurement study and the associated error analysis, we demonstrate that indirect measurements, such as King and Internet Coordinate Systems (ICS), can only achieve a coarse estimation of peers’ network location and those methods based on pure indirect measurements cannot lead to a good relay selection. We also demonstrate that there exists significant error amplification of the commonly used “best-out-of-K” selection methodology using three RTT data sets publicly available. We propose a two-phase approach to achieve efficient relay discovery and accurate relay selection. Indirect measurements are used to narrow down a small number of high-quality relay candidates and the final relay selection is refined based on direct probing. This two-phase approach enjoys an efficient implementation using the Distributed-Hash-Table (DHT). When the DHT is constructed, the node keys carry the location information and they are generated scalably using indirect measurements, such as the ICS coordinates. The relay discovery is achieved efficiently utilizing the DHT-based search. We evaluated various aspects of this DHT-based approach, including the DHT indexing procedure, key generation under peer churn and message costs. PMID:28410384

Relay discovery and selection for large-scale P2P streaming.

PubMed

Zhang, Chengwei; Wang, Angela Yunxian; Hei, Xiaojun

2017-01-01

In peer-to-peer networks, application relays have been commonly used to provide various networking services. The service performance often improves significantly if a relay is selected appropriately based on its network location. In this paper, we studied the location-aware relay discovery and selection problem for large-scale P2P streaming networks. In these large-scale and dynamic overlays, it incurs significant communication and computation cost to discover a sufficiently large relay candidate set and further to select one relay with good performance. The network location can be measured directly or indirectly with the tradeoffs between timeliness, overhead and accuracy. Based on a measurement study and the associated error analysis, we demonstrate that indirect measurements, such as King and Internet Coordinate Systems (ICS), can only achieve a coarse estimation of peers' network location and those methods based on pure indirect measurements cannot lead to a good relay selection. We also demonstrate that there exists significant error amplification of the commonly used "best-out-of-K" selection methodology using three RTT data sets publicly available. We propose a two-phase approach to achieve efficient relay discovery and accurate relay selection. Indirect measurements are used to narrow down a small number of high-quality relay candidates and the final relay selection is refined based on direct probing. This two-phase approach enjoys an efficient implementation using the Distributed-Hash-Table (DHT). When the DHT is constructed, the node keys carry the location information and they are generated scalably using indirect measurements, such as the ICS coordinates. The relay discovery is achieved efficiently utilizing the DHT-based search. We evaluated various aspects of this DHT-based approach, including the DHT indexing procedure, key generation under peer churn and message costs.

Phosphoproteome of Pristionchus pacificus provides insights into architecture of signaling networks in nematode models.

PubMed

Borchert, Nadine; Krug, Karsten; Gnad, Florian; Sinha, Amit; Sommer, Ralf J; Macek, Boris

2012-12-01

Pristionchus pacificus is a nematode that is increasingly used as a model organism in evolutionary biology. The genome of P. pacificus differs markedly from that of C. elegans, with a high number of orphan genes that are restricted to P. pacificus and have no homologs in other species. To gain insight into the architecture of signal transduction networks in model nematodes, we performed a large-scale qualitative phosphoproteome analysis of P. pacificus. Using two-stage enrichment of phosphopeptides from a digest of P. pacificus proteins and their subsequent analysis via high accuracy MS, we detected and localized 6,809 phosphorylation events on 2,508 proteins. We compared the detected P. pacificus phosphoproteome to the recently published phosphoproteome of C. elegans. The overall numbers and functional classes of phosphoproteins were similar between the two organisms. Interestingly, the products of orphan genes were significantly underrepresented among the detected P. pacificus phosphoproteins. We defined the theoretical kinome of P. pacificus and compared it to that of C. elegans. While tyrosine kinases were slightly underrepresented in the kinome of P. pacificus, all major classes of kinases were present in both organisms. Application of our kinome annotation to a recent transcriptomic study of dauer and mixed stage populations showed that Ser/Thr and Tyr kinases show similar expression levels in P. pacificus but not in C. elegans. This study presents the first systematic comparison of phosphoproteomes and kinomes of two model nematodes and, as such, will be a useful resource for comparative studies of their signal transduction networks.

Multi-pathway Kinase Signatures of Multipotent Stromal Cells are Predictive for Osteogenic Differentiation

PubMed Central

Platt, Manu O.; Wilder, Catera L.; Wells, Alan; Griffith, Linda G.; Lauffenburger, Douglas A.

2010-01-01

Bone marrow-derived multi-potent stromal cells (MSCs) offer great promise for regenerating tissue. While certain transcription factors have been identified in association with tendency toward particular MSC differentiation phenotypes, the regulatory network of key receptor-mediated signaling pathways activated by extracellular ligands that induce various differentiation responses remain poorly understood. Attempts to predict differentiation fate tendencies from individual pathways in isolation are problematic due to the complex pathway interactions inherent in signaling networks. Accordingly, we have undertaken a multi-variate systems approach integrating experimental measurement of multiple kinase pathway activities and osteogenic differentiation in MSCs, together with computational analysis to elucidate quantitative combinations of kinase signals predictive of cell behavior across diverse contexts. In particular, for culture on polymeric biomaterials surfaces presenting tethered epidermal growth factor (tEGF), type-I collagen, neither, or both, we have found that a partial least-squares regression model yields successful prediction of phenotypic behavior on the basis of two principal components comprising the weighted sums of 8 intracellular phosphoproteins: p-EGFR, p-Akt, p-ERK1/2, p-Hsp27, p-c-jun, p-GSK3α/β, p-p38, and p-STAT3. This combination provides strongest predictive capability for 21-day differentiated phenotype status when calculated from day-7 signal measurements (99%); day-4 (88%) and day-14 (89%) signal measurements are also significantly predictive, indicating a broad time-frame during MSC osteogenesis wherein multiple pathways and states of the kinase signaling network are quantitatively integrated to regulate gene expression, cell processes, and ultimately, cell fate. PMID:19750537

P³DB 3.0: From plant phosphorylation sites to protein networks.

PubMed

Yao, Qiuming; Ge, Huangyi; Wu, Shangquan; Zhang, Ning; Chen, Wei; Xu, Chunhui; Gao, Jianjiong; Thelen, Jay J; Xu, Dong

2014-01-01

In the past few years, the Plant Protein Phosphorylation Database (P(3)DB, http://p3db.org) has become one of the most significant in vivo data resources for studying plant phosphoproteomics. We have substantially updated P(3)DB with respect to format, new datasets and analytic tools. In the P(3)DB 3.0, there are altogether 47 923 phosphosites in 16 477 phosphoproteins curated across nine plant organisms from 32 studies, which have met our multiple quality standards for acquisition of in vivo phosphorylation site data. Centralized by these phosphorylation data, multiple related data and annotations are provided, including protein-protein interaction (PPI), gene ontology, protein tertiary structures, orthologous sequences, kinase/phosphatase classification and Kinase Client Assay (KiC Assay) data--all of which provides context for the phosphorylation event. In addition, P(3)DB 3.0 incorporates multiple network viewers for the above features, such as PPI network, kinase-substrate network, phosphatase-substrate network, and domain co-occurrence network to help study phosphorylation from a systems point of view. Furthermore, the new P(3)DB reflects a community-based design through which users can share datasets and automate data depository processes for publication purposes. Each of these new features supports the goal of making P(3)DB a comprehensive, systematic and interactive platform for phosphoproteomics research.

Network-assisted investigation of virulence and antibiotic-resistance systems in Pseudomonas aeruginosa

NASA Astrophysics Data System (ADS)

Hwang, Sohyun; Kim, Chan Yeong; Ji, Sun-Gou; Go, Junhyeok; Kim, Hanhae; Yang, Sunmo; Kim, Hye Jin; Cho, Ara; Yoon, Sang Sun; Lee, Insuk

2016-05-01

Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively studied, approximately one-third of the functional genome remains unknown. With the emergence of antibiotic-resistant strains of P. aeruginosa, there is an urgent need to develop novel antibiotic and anti-virulence strategies, which may be facilitated by an approach that explores P. aeruginosa gene function in systems-level models. Here, we present a genome-wide functional network of P. aeruginosa genes, PseudomonasNet, which covers 98% of the coding genome, and a companion web server to generate functional hypotheses using various network-search algorithms. We demonstrate that PseudomonasNet-assisted predictions can effectively identify novel genes involved in virulence and antibiotic resistance. Moreover, an antibiotic-resistance network based on PseudomonasNet reveals that P. aeruginosa has common modular genetic organisations that confer increased or decreased resistance to diverse antibiotics, which accounts for the pervasiveness of cross-resistance across multiple drugs. The same network also suggests that P. aeruginosa has developed mechanism of trade-off in resistance across drugs by altering genetic interactions. Taken together, these results clearly demonstrate the usefulness of a genome-scale functional network to investigate pathogenic systems in P. aeruginosa.

A Compact Optical Instrument with Artificial Neural Network for pH Determination

PubMed Central

Capel-Cuevas, Sonia; López-Ruiz, Nuria; Martinez-Olmos, Antonio; Cuéllar, Manuel P.; Pegalajar, Maria del Carmen; Palma, Alberto José; de Orbe-Payá, Ignacio; Capitán-Vallvey, Luis Fermin

2012-01-01

The aim of this work was the determination of pH with a sensor array-based optical portable instrument. This sensor array consists of eleven membranes with selective colour changes at different pH intervals. The method for the pH calculation is based on the implementation of artificial neural networks that use the responses of the membranes to generate a final pH value. A multi-objective algorithm was used to select the minimum number of sensing elements required to achieve an accurate pH determination from the neural network, and also to minimise the network size. This helps to minimise instrument and array development costs and save on microprocessor energy consumption. A set of artificial neural networks that fulfils these requirements is proposed using different combinations of the membranes in the sensor array, and is evaluated in terms of accuracy and reliability. In the end, the network including the response of the eleven membranes in the sensor was selected for validation in the instrument prototype because of its high accuracy. The performance of the instrument was evaluated by measuring the pH of a large set of real samples, showing that high precision can be obtained in the full range. PMID:22778668

On the sufficiency of pairwise interactions in maximum entropy models of networks

NASA Astrophysics Data System (ADS)

Nemenman, Ilya; Merchan, Lina

Biological information processing networks consist of many components, which are coupled by an even larger number of complex multivariate interactions. However, analyses of data sets from fields as diverse as neuroscience, molecular biology, and behavior have reported that observed statistics of states of some biological networks can be approximated well by maximum entropy models with only pairwise interactions among the components. Based on simulations of random Ising spin networks with p-spin (p > 2) interactions, here we argue that this reduction in complexity can be thought of as a natural property of some densely interacting networks in certain regimes, and not necessarily as a special property of living systems. This work was supported in part by James S. McDonnell Foundation Grant No. 220020321.

Towards Accurate Node-Based Detection of P2P Botnets

PubMed Central

2014-01-01

Botnets are a serious security threat to the current Internet infrastructure. In this paper, we propose a novel direction for P2P botnet detection called node-based detection. This approach focuses on the network characteristics of individual nodes. Based on our model, we examine node's flows and extract the useful features over a given time period. We have tested our approach on real-life data sets and achieved detection rates of 99-100% and low false positives rates of 0–2%. Comparison with other similar approaches on the same data sets shows that our approach outperforms the existing approaches. PMID:25089287

JXTA: A Technology Facilitating Mobile P2P Health Management System

PubMed Central

Rajkumar, Rajasekaran; Nallani Chackravatula Sriman, Narayana Iyengar

2012-01-01

Objectives Mobile JXTA (Juxtapose) gaining momentum and has attracted the interest of doctors and patients through P2P service that transmits messages. Audio and video can also be transmitted through JXTA. The use of mobile streaming mechanism with the support of mobile hospital management and healthcare system would enable better interaction between doctors, nurses, and the hospital. Experimental results demonstrate good performance in comparison with conventional systems. This study evaluates P2P JXTA/JXME (JXTA functionality to MIDP devices.) which facilitates peer-to-peer application+ using mobile-constraint devices. Also a proven learning algorithm was used to automatically send and process sorted patient data to nurses. Methods From December 2010 to December 2011, a total of 500 patients were referred to our hospital due to minor health problems and were monitored. We selected all of the peer groups and the control server, which controlled the BMO (Block Medical Officer) peer groups and BMO through the doctor peer groups, and prescriptions were delivered to the patient’s mobile phones through the JXTA/ JXME network. Results All 500 patients were registered in the JXTA network. Among these, 300 patient histories were referred to the record peer group by the doctors, 100 patients were referred to the external doctor peer group, and 100 patients were registered as new users in the JXTA/JXME network. Conclusion This system was developed for mobile streaming applications and was designed to support the mobile health management system using JXTA/ JXME. The simulated results show that this system can carry out streaming audio and video applications. Controlling and monitoring by the doctor peer group makes the system more flexible and structured. Enhanced studies are needed to improve knowledge mining and cloud-based M health management technology in comparison with the traditional system. PMID:24159509

Na/Ca Intermixing around Silicate and Phosphate Groups in Bioactive Phosphosilicate Glasses Revealed by Heteronuclear Solid-State NMR and Molecular Dynamics Simulations.

PubMed

Mathew, Renny; Stevensson, Baltzar; Edén, Mattias

2015-04-30

We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR. We introduce an approach for quantifying the extent of Na(+)/Ca(2+) ordering around a given QP(n) or QSi(n) group, encoded by the preference factor 0⩽ PM ⩽ 1 conveying the relative weights of a random cation intermixing (PM = 0) and complete preference/ordering (PM = 1) for one of the species M, which represents either Na(+) or Ca(2+). The MD-derived preference factors reveal phosphate and silicate species surrounded by Na(+)/Ca(2+) ions intermixed nearly randomly (PM ≲ 0.15), except for the QSi(4) and QSi(1) groups, which manifest more significant cation ordering with preference for Na+ and Ca2+, respectively. The overall weak preferences are essentially independent of the Si and P contents of the glass, whereas PM primarily correlates with the total amount of network modifiers: as the latter is increased, the Na/Ca distribution around the {QP(0), QSi(1), QSi(2)} groups with preference for Ca2(+ )tend to randomize (i.e., PCa decreases), while the PNa-values grow slightly for the {QP(1), QSi(3), QSi(4)} species already preferring coordination of Na. The set of experimental preference factors {PCa} for the orthophosphate (QP(0)) groups extracted from (31)P{(23)Na} REAPDOR NMR-derived M2(P–Na) dipolar second moments agrees well with the MD-generated counterparts. Our results on the Na/Ca intermixing in soda-lime-silicate glasses are discussed in relation to previous reports, highlighting the dependence of the conclusion on the approach to data evaluation.

Parallel performance optimizations on unstructured mesh-based simulations

DOE PAGES

Sarje, Abhinav; Song, Sukhyun; Jacobsen, Douglas; ...

2015-06-01

This paper addresses two key parallelization challenges the unstructured mesh-based ocean modeling code, MPAS-Ocean, which uses a mesh based on Voronoi tessellations: (1) load imbalance across processes, and (2) unstructured data access patterns, that inhibit intra- and inter-node performance. Our work analyzes the load imbalance due to naive partitioning of the mesh, and develops methods to generate mesh partitioning with better load balance and reduced communication. Furthermore, we present methods that minimize both inter- and intranode data movement and maximize data reuse. Our techniques include predictive ordering of data elements for higher cache efficiency, as well as communication reduction approaches.more » We present detailed performance data when running on thousands of cores using the Cray XC30 supercomputer and show that our optimization strategies can exceed the original performance by over 2×. Additionally, many of these solutions can be broadly applied to a wide variety of unstructured grid-based computations.« less

Tight Coupling of Astrocyte pH Dynamics to Epileptiform Activity Revealed by Genetically Encoded pH Sensors.

PubMed

Raimondo, Joseph V; Tomes, Hayley; Irkle, Agnese; Kay, Louise; Kellaway, Lauriston; Markram, Henry; Millar, Robert P; Akerman, Colin J

2016-06-29

Astrocytes can both sense and shape the evolution of neuronal network activity and are known to possess unique ion regulatory mechanisms. Here we explore the relationship between astrocytic intracellular pH dynamics and the synchronous network activity that occurs during seizure-like activity. By combining confocal and two-photon imaging of genetically encoded pH reporters with simultaneous electrophysiological recordings, we perform pH measurements in defined cell populations and relate these to ongoing network activity. This approach reveals marked differences in the intracellular pH dynamics between hippocampal astrocytes and neighboring pyramidal neurons in rodent in vitro models of epilepsy. With three different genetically encoded pH reporters, astrocytes are observed to alkalinize during epileptiform activity, whereas neurons are observed to acidify. In addition to the direction of pH change, the kinetics of epileptiform-associated intracellular pH transients are found to differ between the two cell types, with astrocytes displaying significantly more rapid changes in pH. The astrocytic alkalinization is shown to be highly correlated with astrocytic membrane potential changes during seizure-like events and mediated by an electrogenic Na(+)/HCO3 (-) cotransporter. Finally, comparisons across different cell-pair combinations reveal that astrocytic pH dynamics are more closely related to network activity than are neuronal pH dynamics. This work demonstrates that astrocytes exhibit distinct pH dynamics during periods of epileptiform activity, which has relevance to multiple processes including neurometabolic coupling and the control of network excitability. Dynamic changes in intracellular ion concentrations are central to the initiation and progression of epileptic seizures. However, it is not known how changes in intracellular H(+) concentration (ie, pH) differ between different cell types during seizures. Using recently developed pH-sensitive proteins, we demonstrate that astrocytes undergo rapid alkalinization during periods of seizure-like activity, which is in stark contrast to the acidification that occurs in neighboring neurons. Rapid astrocytic pH changes are highly temporally correlated with seizure activity, are mediated by an electrogenic Na(+)/HCO3- cotransporter, and are more tightly coupled to network activity than are neuronal pH changes. As pH has profound effects on signaling in the nervous system, this work has implications for our understanding of seizure dynamics. Copyright © 2016 the authors 0270-6474/16/367002-12$15.00/0.

Critical behavior of the contact process on small-world networks

NASA Astrophysics Data System (ADS)

Ferreira, Ronan S.; Ferreira, Silvio C.

2013-11-01

We investigate the role of clustering on the critical behavior of the contact process (CP) on small-world networks using the Watts-Strogatz (WS) network model with an edge rewiring probability p. The critical point is well predicted by a homogeneous cluster-approximation for the limit of vanishing clustering ( p → 1). The critical exponents and dimensionless moment ratios of the CP are in agreement with those predicted by the mean-field theory for any p > 0. This independence on the network clustering shows that the small-world property is a sufficient condition for the mean-field theory to correctly predict the universality of the model. Moreover, we compare the CP dynamics on WS networks with rewiring probability p = 1 and random regular networks and show that the weak heterogeneity of the WS network slightly changes the critical point but does not alter other critical quantities of the model.

VoIPNET: A Software Based Communications Tool for Low-Bandwidth Networks

DTIC Science & Technology

2007-06-01

Plan Suplemental Tools. <http://www.dir.state.tx.us/pubs/framework/gate2/riskplan/ Deitel , H.M. and Deitel , P.J. Java: How To Program . 5th...Up. 3rd Edition. California: McGraw-Hill, 2003. Deitel , H.M. and Deitel , P.J. C++: How to Program . 5th Edition. New Jersey: Prentice Hall...users. It is possible for a single user to consume all available bandwidth. Hop limits are programmed during EPLRS 8 network planning. CSMA

Leveraging Structural Characteristics of Interdependent Networks to Model Non-linear Cascading Characteristics

DTIC Science & Technology

2015-06-29

17.476 237.18 17.5 237.2 91.64216359 6.752418 -20- References Asuncion, A., Welling, M., Smyth, P., & Teh , P. Y. ( 2009 ). On Smoothing and inference...networks of interdependent programs [Lewin 1999, Flowe et al., 2009 ]. Also, the acquisition paradigm established in statute 10 U.S.C. 2434, policy...results. Number of topics (k) for input data: Quality of results of modeling can be measured using a factor called perplexity (Asuncion et al. 2009

p53-repressed miRNAs are involved with E2F in a feed-forward loop promoting proliferation

PubMed Central

Brosh, Ran; Shalgi, Reut; Liran, Atar; Landan, Gilad; Korotayev, Katya; Nguyen, Giang Huong; Enerly, Espen; Johnsen, Hilde; Buganim, Yosef; Solomon, Hilla; Goldstein, Ido; Madar, Shalom; Goldfinger, Naomi; Børresen-Dale, Anne-Lise; Ginsberg, Doron; Harris, Curtis C; Pilpel, Yitzhak; Oren, Moshe; Rotter, Varda

2008-01-01

Normal cell growth is governed by a complicated biological system, featuring multiple levels of control, often deregulated in cancers. The role of microRNAs (miRNAs) in the control of gene expression is now increasingly appreciated, yet their involvement in controlling cell proliferation is still not well understood. Here we investigated the mammalian cell proliferation control network consisting of transcriptional regulators, E2F and p53, their targets and a family of 15 miRNAs. Indicative of their significance, expression of these miRNAs is downregulated in senescent cells and in breast cancers harboring wild-type p53. These miRNAs are repressed by p53 in an E2F1-mediated manner. Furthermore, we show that these miRNAs silence antiproliferative genes, which themselves are E2F1 targets. Thus, miRNAs and transcriptional regulators appear to cooperate in the framework of a multi-gene transcriptional and post-transcriptional feed-forward loop. Finally, we show that, similarly to p53 inactivation, overexpression of representative miRNAs promotes proliferation and delays senescence, manifesting the detrimental phenotypic consequence of perturbations in this circuit. Taken together, these findings position miRNAs as novel key players in the mammalian cellular proliferation network. PMID:19034270

Genome-Wide Gene-Sodium Interaction Analyses on Blood Pressure: The Genetic Epidemiology Network of Salt-Sensitivity Study.

PubMed

Li, Changwei; He, Jiang; Chen, Jing; Zhao, Jinying; Gu, Dongfeng; Hixson, James E; Rao, Dabeeru C; Jaquish, Cashell E; Gu, Charles C; Chen, Jichun; Huang, Jianfeng; Chen, Shufeng; Kelly, Tanika N

2016-08-01

We performed genome-wide analyses to identify genomic loci that interact with sodium to influence blood pressure (BP) using single-marker-based (1 and 2 df joint tests) and gene-based tests among 1876 Chinese participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. Among GenSalt participants, the average of 3 urine samples was used to estimate sodium excretion. Nine BP measurements were taken using a random zero sphygmomanometer. A total of 2.05 million single-nucleotide polymorphisms were imputed using Affymetrix 6.0 genotype data and the Chinese Han of Beijing and Japanese of Tokyo HapMap reference panel. Promising findings (P<1.00×10(-4)) from GenSalt were evaluated for replication among 775 Chinese participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Single-nucleotide polymorphism and gene-based results were meta-analyzed across the GenSalt and MESA studies to determine genome-wide significance. The 1 df tests identified interactions for UST rs13211840 on diastolic BP (P=3.13×10(-9)). The 2 df tests additionally identified associations for CLGN rs2567241 (P=3.90×10(-12)) and LOC105369882 rs11104632 (P=4.51×10(-8)) with systolic BP. The CLGN variant rs2567241 was also associated with diastolic BP (P=3.11×10(-22)) and mean arterial pressure (P=2.86×10(-15)). Genome-wide gene-based analysis identified MKNK1 (P=6.70×10(-7)), C2orf80 (P<1.00×10(-12)), EPHA6 (P=2.88×10(-7)), SCOC-AS1 (P=4.35×10(-14)), SCOC (P=6.46×10(-11)), CLGN (P=3.68×10(-13)), MGAT4D (P=4.73×10(-11)), ARHGAP42 (P≤1.00×10(-12)), CASP4 (P=1.31×10(-8)), and LINC01478 (P=6.75×10(-10)) that were associated with at least 1 BP phenotype. In summary, we identified 8 novel and 1 previously reported BP loci through the examination of single-nucleotide polymorphism and gene-based interactions with sodium. © 2016 American Heart Association, Inc.

Computer-mediated support group intervention for parents.

PubMed

Bragadóttir, Helga

2008-01-01

The purpose of this study was to evaluate the feasibility of a computer-mediated support group (CMSG) intervention for parents whose children had been diagnosed with cancer. An evaluative one-group, before-and-after research design. A CMSG, an unstructured listserve group where participants used their E-mail for communication, was conducted over a 4-month period. Participation in the CMSG was offered to parents in Iceland whose children had completed cancer treatment in the past 5 years. Outcome measures were done: before the intervention (Time 1), after 2 months of intervention (Time 2) and after 4 months of intervention (Time 3) when the project ended. Measures included: demographic and background variables; health related vulnerability factors of parents: anxiety, depression, somatization, and stress; perceived mutual support; and use of the CMSG. Data were collected from November 2002 to June 2003. Twenty-one of 58 eligible parents participated in the study, with 71% retention rate for both post-tests. Mothers' depression decreased significantly from Time 2 to Time 3 (p<.03). Fathers' anxiety decreased significantly from Time 1 to Time 3 (p<.01). Fathers' stress decreased significantly from Time 2 to Time 3 (p<.02). To some extent, mothers and fathers perceived mutual support from participating in the CMSG. Both mothers and fathers used the CMSG by reading messages. Messages were primarily written by mothers. Study findings support further development of CMSGs for parents whose children have been diagnosed with cancer. Using computer technology for support is particularly useful for dispersed populations and groups that have restrictions on their time. Computer-mediated support groups have been shown to be a valuable addition to, or substitute for, a traditional face-to-face mutual support group and might suit both genders equally.

Transcriptional networks associated with the immune system are disrupted by organochlorine pesticides in largemouth bass (Micropterus salmoides) ovary.

PubMed

Martyniuk, Christopher J; Doperalski, Nicholas J; Feswick, April; Prucha, Melinda S; Kroll, Kevin J; Barber, David S; Denslow, Nancy D

2016-08-01

Largemouth bass (Micropterus salmoides) inhabiting Lake Apopka, Florida are exposed to high levels of persistent organochlorine pesticides (OCPs) and dietary uptake is a significant route of exposure for these apex predators. The objectives of this study were to determine the dietary effects of two organochlorine pesticides (p, p'-dichlorodiphenyldichloroethylene; p, p' DDE and methoxychlor; MXC) on the reproductive axis of largemouth bass. Reproductive bass (late vitellogenesis) were fed one of the following diets: control pellets, 125ppm p, p'-DDE, or 10ppm MXC (mg/kg) for 84days. Due to the fact that both p,p' DDE and MXC have anti-androgenic properties, the anti-androgenic pharmaceutical flutamide was fed to a fourth group of largemouth bass (750ppm). Following a 3 month exposure, fish incorporated p,p' DDE and MXC into both muscle and ovary tissue, with the ovary incorporating 3 times more organochlorine pesticides compared to muscle. Endpoints assessed were those related to reproduction due to previous studies demonstrating that these pesticides impact the reproductive axis and we hypothesized that a dietary exposure would result in impaired reproduction. However, oocyte distribution, gonadosomatic index, plasma vitellogenin, and plasma sex steroids (17β-estradiol, E2 and testosterone, T) were not different between control animals and contaminant-fed largemouth bass. Moreover, neither p, p' DDE nor MXC affected E2 or T production in ex vivo oocyte cultures from chemical-fed largemouth bass. However, both pesticides did interfere with the normal upregulation of androgen receptor that is observed in response to human chorionic gonadotropin in ex vivo cultures, an observation that may be related to their anti-androgenic properties. Transcriptomics profiling in the ovary revealed that gene networks related to cell processes such as leukocyte cell adhesion, ossification, platelet function and inhibition, xenobiotic metabolism, fibrinolysis, and thermoregulation were altered by p, p' DDE, MXC, and flutamide. Interestingly, immune-related gene networks were suppressed by all three chemicals. The data suggest that p, p' DDE and flutamide affected more genes in common with each other than either chemical with MXC, consistent with studies suggesting that p, p' DDE is a more potent anti-androgen than MXC. These data demonstrate that reproductive health was not affected by these specific dietary treatments, but rather the immune system, which may be a significant target of organochlorine pesticides. The interaction between the reproductive and immune systems should be considered in future studies on these legacy and persistent pesticides. Copyright © 2016 Elsevier B.V. All rights reserved.

MODFLOW–USG version 1: An unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation

USGS Publications Warehouse

Panday, Sorab; Langevin, Christian D.; Niswonger, Richard G.; Ibaraki, Motomu; Hughes, Joseph D.

2013-01-01

A new version of MODFLOW, called MODFLOW–USG (for UnStructured Grid), was developed to support a wide variety of structured and unstructured grid types, including nested grids and grids based on prismatic triangles, rectangles, hexagons, and other cell shapes. Flexibility in grid design can be used to focus resolution along rivers and around wells, for example, or to subdiscretize individual layers to better represent hydrostratigraphic units. MODFLOW–USG is based on an underlying control volume finite difference (CVFD) formulation in which a cell can be connected to an arbitrary number of adjacent cells. To improve accuracy of the CVFD formulation for irregular grid-cell geometries or nested grids, a generalized Ghost Node Correction (GNC) Package was developed, which uses interpolated heads in the flow calculation between adjacent connected cells. MODFLOW–USG includes a Groundwater Flow (GWF) Process, based on the GWF Process in MODFLOW–2005, as well as a new Connected Linear Network (CLN) Process to simulate the effects of multi-node wells, karst conduits, and tile drains, for example. The CLN Process is tightly coupled with the GWF Process in that the equations from both processes are formulated into one matrix equation and solved simultaneously. This robustness results from using an unstructured grid with unstructured matrix storage and solution schemes. MODFLOW–USG also contains an optional Newton-Raphson formulation, based on the formulation in MODFLOW–NWT, for improving solution convergence and avoiding problems with the drying and rewetting of cells. Because the existing MODFLOW solvers were developed for structured and symmetric matrices, they were replaced with a new Sparse Matrix Solver (SMS) Package developed specifically for MODFLOW–USG. The SMS Package provides several methods for resolving nonlinearities and multiple symmetric and asymmetric linear solution schemes to solve the matrix arising from the flow equations and the Newton-Raphson formulation, respectively.

p53 and Mdm2 act synergistically to maintain cardiac homeostasis and mediate cardiomyocyte cell cycle arrest through a network of microRNAs.

PubMed

Stanley-Hasnain, Shanna; Hauck, Ludger; Grothe, Daniela; Aschar-Sobbi, Roozbeh; Beca, Sanja; Butany, Jagdish; Backx, Peter H; Mak, Tak W; Billia, Filio

2017-01-01

Defining the roadblocks responsible for cell cycle arrest in adult cardiomyocytes lies at the core of developing cardiac regenerative therapies. p53 and Mdm2 are crucial mediators of cell cycle arrest in proliferative cell types, however, little is known about their function in regulating homeostasis and proliferation in terminally differentiated cell types, like cardiomyocytes. To explore this, we generated a cardiac-specific conditional deletion of p53 and Mdm2 (DKO) in adult mice. Herein we describe the development of a dilated cardiomyopathy, in the absence of cardiac hypertrophy. In addition, DKO hearts exhibited a significant increase in cardiomyocyte proliferation. Further evaluation showed that proliferation was mediated by a significant increase in Cdk2 and cyclin E with downregulation of p21 Cip1 and p27 Kip1 . Comparison of miRNA expression profiles from DKO mouse hearts and controls revealed 11 miRNAs that were downregulated in the DKO hearts and enriched for mRNA targets involved in cell cycle regulation. Knockdown of these miRNAs in neonatal rat cardiomyocytes significantly increased cytokinesis with an upregulation in the expression of crucial cell cycle regulators. These results illustrate the importance of the cooperative activities of p53 and Mdm2 in a network of miRNAs that function to impose a barrier against aberrant cardiomyocyte cell cycle re-entry to maintain cardiac homeostasis.

NANOGOLD decorated by pHLIP peptide: comparative force field study.

PubMed

Kyrychenko, A

2015-05-21

The potential of gold nanoparticles (AuNPs) in therapeutic and diagnostic cancer applications is becoming increasingly recognized, which focuses on their efficient and specific delivery from passive accumulation in tumour tissue to directly targeting tumor-specific biomarkers. AuNPs functionalized by pH low insertion peptide (pHLIP) have recently revealed the capability of targeting acidic tissues and inserting into cell membranes. However, the structure of AuNP-pHLIP conjugates and fundamental gold-peptide interactions still remain unknown. In this study, we have developed a series of molecular dynamics (MD) models reproducing a small gold nanoparticle coupled to pHLIP. We focus on Au135 nanoparticles that comprise a nearly spherical Au core (diameter ∼ 1.4 nm) functionalized with a monomaleimide moiety, mimicking a commercially available monomaleimido NANOGOLD® labelling agent. To probe the structure and folding of pHLIP, which is attached covalently to the maleimide NANOGOLD particle, we have benchmarked the performances of a series of popular, all-atom force fields (FF), including those of OPLS-AA, AMBER03, three variations of CHARMM FFs, as well as united-atom GROMOS G53A6 FF. We found that CHARMMs and OPLSAA FFs predict that in an aqueous salt solution at a neutral pH, pHLIP is partially bound onto the gold surface through some short hydrophobic peptide stretches, while at the same time, a large portion of peptide remains in solution. In contrast, AMBER03 and G53A6 FFs revealed the formation of compact, tightly bound peptide configurations adsorbed onto the nanoparticle core. To reproduce the experimental physical picture of the peptide adsorption onto gold in unfolded and unstructured conformations, our study suggests CHARMM36 and OPLS-AA FFs as a tool of choice for the computational studies of NANOGOLD decorated by pHLIP.

Detecting Peer-to-Peer Botnets in SCADA Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Huan; Cheng, Liang; Chuah, Mooi Choo

Supervisory Control and Data Acquisition (SCADA) systems monitor and control critical infrastructure such as the smart grid. As SCADA systems become increasingly interconnected and adopt more and more cyber-enabled components, the risks of cyber attacks become a major concern. Due to their decentralized organization, peer-to-peer (P2P) botnets are resilient to many existing takedown measures and can be exploited as an effective way to launch cyber attacks on SCADA systems. However, little work has been done to detect P2P botnets in SCADA systems, which carry traffic flows with characteristics significantly different from the Internet. In this paper, we design a P2P-botnetmore » detection method for SCADA systems, leveraging built-in traffic monitoring capabilities of SCADA networking devices. The proposed method consists of two stages. In the first stage, we design a simple feature test to filter out non-P2P hosts, which significantly reduces the data volume for P2P-botnet identification. In the second stage, we jointly consider flow-based and connectivity-based features that effectively set apart bots from benign hosts. We propose to use unsupervised learning for P2P-botnet identification, which not only identifies known P2P botnets but also captures newly emerged ones. Our simulation results show that the proposed system achieves high detection rates with very few false positives. Furthermore, our evaluation shows that the proposed method can detect hosts running P2P SCADA applications that are infected by P2P bots.« less

Network Management of the SPLICE Computer Network.

DTIC Science & Technology

1982-12-01

Approved for public release; distri4ition unlimited. Network lanagenent Df the SPLICE Computer Network by Zriig E. Opal captaini United St~tes larine... structure of the network must leni itself t3 change and reconfiguration, one author [Ref. 2: p.21] recommended that a global bus topology be adopted for...statistics, trace statistics, snapshot statistiZs, artifi - cial traffic generators, auulat on, a network measurement center which includes control, collction

Evolving network simulation study. From regular lattice to scale free network

NASA Astrophysics Data System (ADS)

Makowiec, D.

2005-12-01

The Watts-Strogatz algorithm of transferring the square lattice to a small world network is modified by introducing preferential rewiring constrained by connectivity demand. The evolution of the network is two-step: sequential preferential rewiring of edges controlled by p and updating the information about changes done. The evolving system self-organizes into stationary states. The topological transition in the graph structure is noticed with respect to p. Leafy phase a graph formed by multiple connected vertices (graph skeleton) with plenty of leaves attached to each skeleton vertex emerges when p is small enough to pretend asynchronous evolution. Tangling phase where edges of a graph circulate frequently among low degree vertices occurs when p is large. There exist conditions at which the resulting stationary network ensemble provides networks which degree distribution exhibit power-law decay in large interval of degrees.

Deubiquitinating enzyme regulation of the p53 pathway: A lesson from Otub1

PubMed Central

Sun, Xiao-Xin; Dai, Mu-Shui

2014-01-01

Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes (DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme (E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2. PMID:24920999

The association between social networks and self-rated risk of HIV infection among secondary school students in Moshi Municipality, Tanzania

PubMed Central

Lyimo, Elizabeth J.; Todd, Jim; Rickey, Lisa Ann; Njau, Bernard

2014-01-01

This study describes the social networks of secondary school students in Moshi Municipality, and their association with self-rated risk of human immunodeficiency virus (HIV) infection. A cross-sectional analytical study was conducted among 300 students aged 15–24 years in 5 secondary schools in Moshi, Tanzania. Bonding networks were defined as social groupings of students participating in activities within the school, while bridging networks were groups that included students participating in social groupings from outside of the school environs. A structured questionnaire was used to ask about participation in bonding and bridging social networks and self-rated HIV risk behavior. More participants participated in bonding networks (72%) than in bridging networks (29%). Participation in bridging networks was greater among females (25%) than males (12%, p < .005). Of 300 participants, 88 (29%) were sexually experienced, and of these 62 (70%) considered themselves to be at low risk of HIV infection. Factors associated with self-rated risk of HIV included: type of school (p < .003), family structure (p < .008), being sexually experienced (p < .004), having had sex in the past three months (p < .009), having an extra sexual partner (p < .054) and non-condom use in last sexual intercourse (p < .001), but not the presence or type of social capital. The study found no association between bonding and bridging social networks on self-rated risk of HIV among study participants. However, sexually experienced participants rated themselves at low risk of HIV infection despite practicing unsafe sex. Efforts to raise adolescents’ self-awareness of risk of HIV infection through life skills education and HIV/acquired immunodeficiency syndrome risk reduction strategies may be beneficial to students in this at-risk group. PMID:24641669

Multigrid solution of internal flows using unstructured solution adaptive meshes

NASA Technical Reports Server (NTRS)

Smith, Wayne A.; Blake, Kenneth R.

1992-01-01

This is the final report of the NASA Lewis SBIR Phase 2 Contract Number NAS3-25785, Multigrid Solution of Internal Flows Using Unstructured Solution Adaptive Meshes. The objective of this project, as described in the Statement of Work, is to develop and deliver to NASA a general three-dimensional Navier-Stokes code using unstructured solution-adaptive meshes for accuracy and multigrid techniques for convergence acceleration. The code will primarily be applied, but not necessarily limited, to high speed internal flows in turbomachinery.

Cellular Energetic Status Supervises the Synthesis of Bis-Diphosphoinositol Tetrakisphosphate Independently of AMP-Activated Protein Kinase

PubMed Central

Choi, Kuicheon; Mollapour, Elahe; Choi, Jae H.; Shears, Stephen B.

2009-01-01

Cells aggressively defend adenosine nucleotide homeostasis; intracellular biosensors detect variations in energetic status and communicate with other cellular networks to initiate adaptive responses. Here, we demonstrate some new elements of this communication process, and we show that this networking is compromised by off-target, bioenergetic effects of some popular pharmacological tools. Treatment of cells with 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), so as to simulate elevated AMP levels, reduced the synthesis of bis-diphosphoinositol tetrakisphosphate ([PP]2-InsP4), an intracellular signal that phosphorylates proteins in a kinase-independent reaction. This was a selective effect; levels of other inositol phosphates were unaffected by AICAR. By genetically manipulating cellular AMP-activated protein kinase activity, we showed that it did not mediate these effects of AICAR. Instead, we conclude that the simulation of deteriorating adenosine nucleotide balance itself inhibited [PP]2-InsP4 synthesis. This conclusion is consistent with our demonstrating that oligomycin elevated cellular [AMP] and selectively inhibited [PP]2-InsP4 synthesis without affecting other inositol phosphates. In addition, we report that the short-term increases in [PP]2-InsP4 levels normally seen during hyperosmotic stress were attenuated by 2-(2-chloro-4-iodophenylamino)-N-cyclopropylmethoxy-3,4-difluoro-benzamide (PD184352). The latter is typically considered an exquisitely specific mitogen-activated protein kinase kinase (MEK) inhibitor, but small interfering RNA against MEK or extracellular signal-regulated kinase revealed that this mitogen-activated protein kinase pathway was not involved. Instead, we demonstrate that [PP]2-InsP4 synthesis was inhibited by PD184352 through its nonspecific effects on cellular energy balance. Two other MEK inhibitors, 1,4-diamino-2,3-dicyano-1,4-bis(methylthio)butadiene (U0126) and 2′-amino-3′-methoxyflavone (PD98059), had similar off-target effects. We conclude that the levels and hence the signaling strength of [PP]2-InsP4 is supervised by cellular adenosine nucleotide balance, signifying a new link between signaling and bioenergetic networks. PMID:18460607

The effect of LRRK2 mutations on the cholinergic system in manifest and premanifest stages of Parkinson's disease: a cross-sectional PET study.

PubMed

Liu, Shu-Ying; Wile, Daryl J; Fu, Jessie Fanglu; Valerio, Jason; Shahinfard, Elham; McCormick, Siobhan; Mabrouk, Rostom; Vafai, Nasim; McKenzie, Jess; Neilson, Nicole; Perez-Soriano, Alexandra; Arena, Julieta E; Cherkasova, Mariya; Chan, Piu; Zhang, Jing; Zabetian, Cyrus P; Aasly, Jan O; Wszolek, Zbigniew K; McKeown, Martin J; Adam, Michael J; Ruth, Thomas J; Schulzer, Michael; Sossi, Vesna; Stoessl, A Jon

2018-04-01

Markers of neuroinflammation are increased in some patients with LRRK2 Parkinson's disease compared with individuals with idiopathic Parkinson's disease, suggesting possible differences in disease pathogenesis. Previous PET studies have suggested amplified dopamine turnover and preserved serotonergic innervation in LRRK2 mutation carriers. We postulated that patients with LRRK2 mutations might show abnormalities of central cholinergic activity, even before the diagnosis of Parkinson's disease. Between June, 2009, and December, 2015, we recruited participants from four movement disorder clinics in Canada, Norway, and the USA. Patients with Parkinson's disease were diagnosed by movement disorder neurologists on the basis of the UK Parkinson's Disease Society Brain Bank criteria. LRRK2 carrier status was confirmed by bidirectional Sanger sequencing. We used the PET tracer N- 11 C-methyl-piperidin-4-yl propionate to scan for acetylcholinesterase activity. The primary outcome measure was rate of acetylcholinesterase hydrolysis, calculated using the striatal input method. We compared acetylcholinesterase hydrolysis rates between groups using ANCOVA, with adjustment for age based on the results of linear regression analysis. We recruited 14 patients with LRRK2 Parkinson's disease, 16 LRRK2 mutation carriers without Parkinson's disease, eight patients with idiopathic Parkinson's disease, and 11 healthy controls. We noted significant between-group differences in rates of acetylcholinesterase hydrolysis in cortical regions (average cortex p=0·009, default mode network-related regions p=0·006, limbic network-related regions p=0·020) and the thalamus (p=0·008). LRRK2 mutation carriers without Parkinson's disease had increased acetylcholinesterase hydrolysis rates compared with healthy controls in the cortex (average cortex, p=0·046). Patients with LRRK2 Parkinson's disease had significantly higher acetylcholinesterase activity in some cortical regions (average cortex p=0·043, default mode network-related regions p=0·021) and the thalamus (thalamus p=0·004) compared with individuals with idiopathic disease. Acetylcholinesterase hydrolysis rates in healthy controls were correlated inversely with age. LRRK2 mutations are associated with significantly increased cholinergic activity in the brain in mutation carriers without Parkinson's disease compared with healthy controls and in LRRK2 mutation carriers with Parkinson's disease compared with individuals with idiopathic disease. Changes in cholinergic activity might represent early and sustained attempts to compensate for LRRK2-related dysfunction, or alteration of acetylcholinesterase in non-neuronal cells. Michael J Fox Foundation, National Institutes of Health, and Pacific Alzheimer Research Foundation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural Investigation of Phosphorus in CaO-SiO2-P2O5 Ternary Glass

NASA Astrophysics Data System (ADS)

Wang, Zhanjun; Cai, Shengjia; Zhang, Mei; Guo, Min; Zhang, Zuotai

2017-04-01

The system of CaO-SiO2-P2O5 ternary glass is not only among the major constituents of steelmaking slags in iron and steel industry, but also play a significant role in other industrial process, such as chemical engineering and glass industry. In the present study, the structure of CaO-SiO2-P2O5 ternary glass with varying P2O5 content from 0 to 15 wt pct at a fixed CaO/SiO2 = 1.4 was investigated using molecular dynamics (MD) simulation combined with X-ray photoelectron spectroscopy and Raman spectra techniques. The results indicated that P5+ ions have a higher affinity to Ca2+ ions which are then stripped away from the silicate network with the addition of P2O5, resulting in the formation of Ca-O-P and Si-O-Si linkages. In addition, almost all P5+ ions displayed as {{Q}}_{{P}}0 ( {{Q}}_{{P}}n , n is the number of bridging oxygen in one [PO4]-tetrahedra units) and a small fraction of P5+ ions behave as {{Q}}_{{P}}1 (P-O-P) and P-O-Si. The enhanced degree of polymerization can be detected from the increase of {{X}}_{{Si}}3 and X_{{P}}1 /X_{{P}}0 (mole fraction of {{Q}}_{{Si}}i or {{Q}}_{{P}}i ). Furthermore, the ratio of Raman scattering coefficients for Q_{{Si}}i /Q_{{Si}}1 and Q_{{P}}i /Q_{{P}}1 were determined by combining MD simulated result with Raman spectra, which were considered to be suitable to the present study.

Elastic, magnetic and electronic properties of iridium phosphide Ir 2P

DOE PAGES

Wang, Pei; Wang, Yonggang; Wang, Liping; ...

2016-02-24

Cubic (space group: Fm3¯m) iridium phosphide, Ir 2P, has been synthesized at high pressure and high temperature. Angle-dispersive synchrotron X-ray diffraction measurements on Ir 2P powder using a diamond-anvil cell at room temperature and high pressures (up to 40.6 GPa) yielded a bulk modulus of B 0 = 306(6) GPa and its pressure derivative B 0'= 6.4(5). Such a high bulk modulus attributed to the short and strongly covalent Ir-P bonds as revealed by first – principles calculations and three-dimensionally distributed [IrP 4] tetrahedron network. Indentation testing on a well–sintered polycrystalline sample yielded the hardness of 11.8(4) GPa. Relatively lowmore » shear modulus of ~64 GPa from theoretical calculations suggests a complicated overall bonding in Ir 2P with metallic, ionic, and covalent characteristics. Additionally, a spin glass behavior is indicated by magnetic susceptibility measurements.« less

Highly sensitive detection and discrimination of LR and YR microcystins based on protein phosphatases and an artificial neural network.

PubMed

Covaci, O I; Sassolas, A; Alonso, G A; Muñoz, R; Radu, G L; Bucur, B; Marty, J-L

2012-08-01

The inhibition characteristics of three different protein phosphatases by three microcystin (MC) variants--LR, YR, and RR--were studied. The corresponding K (I) for each enzyme-MC couple was calculated. The toxicity of MC varies in the following order: MC-LR > MC-YR > MC-RR. The sensitivity of the enzymes increased in the following order: mutant PP2A < mutant PP1 < natural PP2A. The best limit of detection obtained was 21.2 pM MC-LR using the most sensible enzyme. Methanol, ethanol, and acetonitrile up to 2 % (v/v) may be used in inhibition measurements. An artificial neural network (ANN) was used to discriminate two MC variants--LR and YR--using the differences in inhibition percentages measured with mutant PP1 and natural PP2A. The ANN is able to analyze mixtures with concentrations ranging from 8 to 98 pM MC-LR and 31 to 373 pM MC-YR.

Methane emissions from a human-dominated lowland coastal river network (Shanghai, China)

NASA Astrophysics Data System (ADS)

Wang, D.; Yu, Z.

2017-12-01

Evasion of methane (CH4) in streams and rivers play a critical role in global carbon (C) cycle, offsetting the C uptake by terrestrial ecosystems. However, little is known about CH4 emissions from lowland coastal rivers profoundly modified by anthropogenic perturbations. Here, we report results from a long-term, large-scale study of CH4 partial pressures (pCH4) and evasion rates in the Shanghai river network. The spatiotemporal variability of pCH4 was examined along a land-use gradient and the annual CH4 evasion were estimated to assess its role in regional C budget. During the study period, the median pCH4 from 87 surveyed rivers was 241 μatm. CH4 was oversaturated throughout the river network, CH4 hotpots were concentrated in the small urban rivers and highly discharge-dependent. The annual median fCH4 for each site ranged from 3.1 mg C•m-2•d-1 to 296.6 mg C•m-2•d-1. The annual CH4 evasion were 105 Gg CO2-eq•yr-1 and 96 Gg CO2-eq•yr-1 for the entire river network and the mainland rivers, respectively. Given the rapid urbanization in global coastal areas, more research is needed to quantify the role of lowland coastal rivers as a major landscape C source in global C budget.

Differential endosomal sorting of a novel P2Y12 purinoreceptor mutant.

PubMed

Cunningham, Margaret R; Nisar, Shaista P; Cooke, Alexandra E; Emery, Elizabeth D; Mundell, Stuart J

2013-05-01

P2Y12 receptor internalization and recycling play an essential role in ADP-induced platelet activation. Recently, we identified a patient with a mild bleeding disorder carrying a heterozygous mutation of P2Y12 (P341A) whose P2Y12 receptor recycling was significantly compromised. Using human cell line models, we identified key proteins regulating wild-type (WT) P2Y12 recycling and investigated P2Y12 -P341A receptor traffic. Treatment with ADP resulted in delayed Rab5-dependent internalization of P341A when compared with WT P2Y12 . While WT P2Y12 rapidly recycled back to the membrane via Rab4 and Rab11 recycling pathways, limited P341A recycling was observed, which relied upon Rab11 activity. Although minimal receptor degradation was evident, P341A was localized in Rab7-positive endosomes with considerable agonist-dependent accumulation in the trans-Golgi network (TGN). Rab7 activity is known to facilitate recruitment of retromer complex proteins to endosomes to transport cargo to the TGN. Here, we identified that P341A colocalized with Vps26; depletion of which blocked limited recycling and promoted receptor degradation. This study has identified key points of divergence in the endocytic traffic of P341A versus WT-P2Y12 . Given that these pathways are retained in human platelets, this research helps define the molecular mechanisms regulating P2Y12 receptor traffic and explain the compromised receptor function in the platelets of the P2Y12 -P341A-expressing patient. © 2013 John Wiley & Sons A/S.

Inferring Plasmodium vivax Transmission Networks from Tempo-Spatial Surveillance Data

PubMed Central

Shi, Benyun; Liu, Jiming; Zhou, Xiao-Nong; Yang, Guo-Jing

2014-01-01

Background The transmission networks of Plasmodium vivax characterize how the parasite transmits from one location to another, which are informative and insightful for public health policy makers to accurately predict the patterns of its geographical spread. However, such networks are not apparent from surveillance data because P. vivax transmission can be affected by many factors, such as the biological characteristics of mosquitoes and the mobility of human beings. Here, we pay special attention to the problem of how to infer the underlying transmission networks of P. vivax based on available tempo-spatial patterns of reported cases. Methodology We first define a spatial transmission model, which involves representing both the heterogeneous transmission potential of P. vivax at individual locations and the mobility of infected populations among different locations. Based on the proposed transmission model, we further introduce a recurrent neural network model to infer the transmission networks from surveillance data. Specifically, in this model, we take into account multiple real-world factors, including the length of P. vivax incubation period, the impact of malaria control at different locations, and the total number of imported cases. Principal Findings We implement our proposed models by focusing on the P. vivax transmission among 62 towns in Yunnan province, People's Republic China, which have been experiencing high malaria transmission in the past years. By conducting scenario analysis with respect to different numbers of imported cases, we can (i) infer the underlying P. vivax transmission networks, (ii) estimate the number of imported cases for each individual town, and (iii) quantify the roles of individual towns in the geographical spread of P. vivax. Conclusion The demonstrated models have presented a general means for inferring the underlying transmission networks from surveillance data. The inferred networks will offer new insights into how to improve the predictability of P. vivax transmission. PMID:24516684

Structural network alterations and neurological dysfunction in cerebral amyloid angiopathy

PubMed Central

Reijmer, Yael D.; Fotiadis, Panagiotis; Martinez-Ramirez, Sergi; Salat, David H.; Schultz, Aaron; Shoamanesh, Ashkan; Ayres, Alison M.; Vashkevich, Anastasia; Rosas, Diana; Schwab, Kristin; Leemans, Alexander; Biessels, Geert-Jan; Rosand, Jonathan; Johnson, Keith A.; Viswanathan, Anand; Gurol, M. Edip

2015-01-01

Cerebral amyloid angiopathy is a common form of small-vessel disease and an important risk factor for cognitive impairment. The mechanisms linking small-vessel disease to cognitive impairment are not well understood. We hypothesized that in patients with cerebral amyloid angiopathy, multiple small spatially distributed lesions affect cognition through disruption of brain connectivity. We therefore compared the structural brain network in patients with cerebral amyloid angiopathy to healthy control subjects and examined the relationship between markers of cerebral amyloid angiopathy-related brain injury, network efficiency, and potential clinical consequences. Structural brain networks were reconstructed from diffusion-weighted magnetic resonance imaging in 38 non-demented patients with probable cerebral amyloid angiopathy (69 ± 10 years) and 29 similar aged control participants. The efficiency of the brain network was characterized using graph theory and brain amyloid deposition was quantified by Pittsburgh compound B retention on positron emission tomography imaging. Global efficiency of the brain network was reduced in patients compared to controls (0.187 ± 0.018 and 0.201 ± 0.015, respectively, P < 0.001). Network disturbances were most pronounced in the occipital, parietal, and posterior temporal lobes. Among patients, lower global network efficiency was related to higher cortical amyloid load (r = −0.52; P = 0.004), and to magnetic resonance imaging markers of small-vessel disease including increased white matter hyperintensity volume (P < 0.001), lower total brain volume (P = 0.02), and number of microbleeds (trend P = 0.06). Lower global network efficiency was also related to worse performance on tests of processing speed (r = 0.58, P < 0.001), executive functioning (r = 0.54, P = 0.001), gait velocity (r = 0.41, P = 0.02), but not memory. Correlations with cognition were independent of age, sex, education level, and other magnetic resonance imaging markers of small-vessel disease. These findings suggest that reduced structural brain network efficiency might mediate the relationship between advanced cerebral amyloid angiopathy and neurologic dysfunction and that such large-scale brain network measures may represent useful outcome markers for tracking disease progression. PMID:25367025

Signalling in the epidermis: the E2F cell cycle regulatory pathway in epidermal morphogenesis, regeneration and transformation.

PubMed

Ivanova, Iordanka A; D'Souza, Sudhir J A; Dagnino, Lina

2005-01-01

The epidermis is the outermost layer in the skin, and it is the first line of defence against the environment. The epidermis also provides a barrier against loss of fluids and electrolytes, which is crucial for life. Essential in the maintenance of this tissue is its ability to continually self-renew and regenerate after injury. These two characteristics are critically dependent on the ability of the principal epidermal cell type, the keratinocyte, to proliferate and to respond to differentiation cues. Indeed, the epidermis is a multilayered tissue composed of keratinocyte stem cells and their differentiated progeny. Central for the control of cell proliferation is the E2F transcription factor regulatory network. This signaling network also includes cyclins, cdk, cdk inhibitors and the retinoblastoma (pRb) family of proteins. The biological importance of the E2F/pRb pathway is emphasized by the fact that a majority of human tumours exhibit alterations that disrupt the ability of pRb proteins to inhibit E2F, leading to permanent activation of the latter. Further, E2F is essential for normal epidermal regeneration after injury. Other member of the E2F signaling pathway are also involved in epidermal development and pathophysiology. Thus, whereas the pRb family of proteins is essential for epidermal morphogenesis, abnormal regulation of cyclins and E2F proteins results in tumorgenesis in this tissue. In this review, we discuss the role of each member of this important growth regulatory network in epidermal formation, homeostasis and carcinogenesis.

Signalling In The Epidermis: The E2f Cell Cycle Regulatory Pathway In Epidermal Morphogenesis, Regeneration And Transformation

PubMed Central

2005-01-01

The epidermis is the outermost layer in the skin, and it is the first line of defence against the environment. The epidermis also provides a barrier against loss of fluids and electrolytes, which is crucial for life. Essential in the maintenance of this tissue is its ability to continually self-renew and regenerate after injury. These two characteristics are critically dependent on the ability of the principal epidermal cell type, the keratinocyte, to proliferate and to respond to differentiation cues. Indeed, the epidermis is a multilayered tissue composed of keratinocyte stem cells and their differentiated progeny. Central for the control of cell proliferation is the E2F transcription factor regulatory network. This signaling network also includes cyclins, cdk, cdk inhibitors and the retinoblastoma (pRb) family of proteins. The biological importance of the E2F/pRb pathway is emphasized by the fact that a majority of human tumours exhibit alterations that disrupt the ability of pRb proteins to inhibit E2F, leading to permanent activation of the latter. Further, E2F is essential for normal epidermal regeneration after injury. Other member of the E2F signaling pathway are also involved in epidermal development and pathophysiology. Thus, whereas the pRb family of proteins is essential for epidermal morphogenesis, abnormal regulation of cyclins and E2F proteins results in tumorgenesis in this tissue. In this review, we discuss the role of each member of this important growth regulatory network in epidermal formation, homeostasis and carcinogenesis. PMID:15951853

miRNA-mRNA integrative analysis in primary myelofibrosis CD34+ cells: role of miR-155/JARID2 axis in abnormal megakaryopoiesis

PubMed Central

Norfo, Ruggiero; Zini, Roberta; Pennucci, Valentina; Bianchi, Elisa; Salati, Simona; Guglielmelli, Paola; Bogani, Costanza; Fanelli, Tiziana; Mannarelli, Carmela; Rosti, Vittorio; Pietra, Daniela; Salmoiraghi, Silvia; Bisognin, Andrea; Ruberti, Samantha; Rontauroli, Sebastiano; Sacchi, Giorgia; Prudente, Zelia; Barosi, Giovanni; Cazzola, Mario; Rambaldi, Alessandro; Bortoluzzi, Stefania; Ferrari, Sergio; Tagliafico, Enrico; Vannucchi, Alessandro M.

2014-01-01

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by megakaryocyte (MK) hyperplasia, bone marrow fibrosis, and abnormal stem cell trafficking. PMF may be associated with somatic mutations in JAK2, MPL, or CALR. Previous studies have shown that abnormal MKs play a central role in the pathophysiology of PMF. In this work, we studied both gene and microRNA (miRNA) expression profiles in CD34+ cells from PMF patients. We identified several biomarkers and putative molecular targets such as FGR, LCN2, and OLFM4. By means of miRNA-gene expression integrative analysis, we found different regulatory networks involved in the dysregulation of transcriptional control and chromatin remodeling. In particular, we identified a network gathering several miRNAs with oncogenic potential (eg, miR-155-5p) and targeted genes whose abnormal function has been previously associated with myeloid neoplasms, including JARID2, NR4A3, CDC42, and HMGB3. Because the validation of miRNA-target interactions unveiled JARID2/miR-155-5p as the strongest relationship in the network, we studied the function of this axis in normal and PMF CD34+ cells. We showed that JARID2 downregulation mediated by miR-155-5p overexpression leads to increased in vitro formation of CD41+ MK precursors. These findings suggest that overexpression of miR-155-5p and the resulting downregulation of JARID2 may contribute to MK hyperplasia in PMF. PMID:25097177

Interarrival times of message propagation on directed networks.

PubMed

Mihaljev, Tamara; de Arcangelis, Lucilla; Herrmann, Hans J

2011-08-01

One of the challenges in fighting cybercrime is to understand the dynamics of message propagation on botnets, networks of infected computers used to send viruses, unsolicited commercial emails (SPAM) or denial of service attacks. We map this problem to the propagation of multiple random walkers on directed networks and we evaluate the interarrival time distribution between successive walkers arriving at a target. We show that the temporal organization of this process, which models information propagation on unstructured peer to peer networks, has the same features as SPAM reaching a single user. We study the behavior of the message interarrival time distribution on three different network topologies using two different rules for sending messages. In all networks the propagation is not a pure Poisson process. It shows universal features on Poissonian networks and a more complex behavior on scale free networks. Results open the possibility to indirectly learn about the process of sending messages on networks with unknown topologies, by studying interarrival times at any node of the network.

Interarrival times of message propagation on directed networks

NASA Astrophysics Data System (ADS)

Mihaljev, Tamara; de Arcangelis, Lucilla; Herrmann, Hans J.

2011-08-01

One of the challenges in fighting cybercrime is to understand the dynamics of message propagation on botnets, networks of infected computers used to send viruses, unsolicited commercial emails (SPAM) or denial of service attacks. We map this problem to the propagation of multiple random walkers on directed networks and we evaluate the interarrival time distribution between successive walkers arriving at a target. We show that the temporal organization of this process, which models information propagation on unstructured peer to peer networks, has the same features as SPAM reaching a single user. We study the behavior of the message interarrival time distribution on three different network topologies using two different rules for sending messages. In all networks the propagation is not a pure Poisson process. It shows universal features on Poissonian networks and a more complex behavior on scale free networks. Results open the possibility to indirectly learn about the process of sending messages on networks with unknown topologies, by studying interarrival times at any node of the network.

Monitoring and Indentification Packet in Wireless With Deep Packet Inspection Method

NASA Astrophysics Data System (ADS)

Fali Oklilas, Ahmad; Tasmi

2017-04-01

Layer 2 and Layer 3 are used to make a process of network monitoring, but with the development of applications on the network such as the p2p file sharing, VoIP, encrypted, and many applications that already use the same port, it would require a system that can classify network traffics, not only based on port number classification. This paper reports the implementation of the deep packet inspection method to analyse data packets based on the packet header and payload to be used in packet data classification. If each application can be grouped based on the application layer, then we can determine the pattern of internet users and also to perform network management of computer science department. In this study, a prototype wireless network and applications SSO were developed to detect the active user. The focus is on the ability of open DPI and nDPI in detecting the payload of an application and the results are elaborated in this paper.

``Models'' CAVEAT EMPTOR!!!: ``Toy Models Too-Often Yield Toy-Results''!!!: Statistics, Polls, Politics, Economics, Elections!!!: GRAPH/Network-Physics: ``Equal-Distribution for All'' TRUMP-ED BEC ``Winner-Take-All'' ``Doctor Livingston I Presume?''

NASA Astrophysics Data System (ADS)

Preibus-Norquist, R. N. C.-Grover; Bush-Romney, G. W.-Willard-Mitt; Dimon, J. P.; Adelson-Koch, Sheldon-Charles-David-Sheldon; Krugman-Axelrod, Paul-David; Siegel, Edward Carl-Ludwig; D. N. C./O. F. P./''47''%/50% Collaboration; R. N. C./G. O. P./''53''%/49% Collaboration; Nyt/Wp/Cnn/Msnbc/Pbs/Npr/Ft Collaboration; Ftn/Fnc/Fox/Wsj/Fbn Collaboration; Lb/Jpmc/Bs/Boa/Ml/Wamu/S&P/Fitch/Moodys/Nmis Collaboration

2013-03-01

``Models''? CAVEAT EMPTOR!!!: ``Toy Models Too-Often Yield Toy-Results''!!!: Goldenfeld[``The Role of Models in Physics'', in Lects.on Phase-Transitions & R.-G.(92)-p.32-33!!!]: statistics(Silver{[NYTimes; Bensinger, ``Math-Geerks Clearly-Defeated Pundits'', LATimes, (11/9/12)])}, polls, politics, economics, elections!!!: GRAPH/network/net/...-PHYSICS Barabasi-Albert[RMP (02)] (r,t)-space VERSUS(???) [Where's the Inverse/ Dual/Integral-Transform???] (Benjamin)Franklin(1795)-Fourier(1795; 1897;1822)-Laplace(1850)-Mellin (1902) Brillouin(1922)-...(k,)-space, {Hubbard [The World According to Wavelets,Peters (96)-p.14!!!/p.246: refs.-F2!!!]},and then (2) Albert-Barabasi[]Bose-Einstein quantum-statistics(BEQS) Bose-Einstein CONDENSATION (BEC) versus Bianconi[pvt.-comm.; arXiv:cond-mat/0204506; ...] -Barabasi [???] Fermi-Dirac

Mortality after hemorrhagic stroke: data from general practice (The Health Improvement Network).

PubMed

González-Pérez, Antonio; Gaist, David; Wallander, Mari-Ann; McFeat, Gillian; García-Rodríguez, Luis A

2013-08-06

To investigate short-term case fatality and long-term mortality after intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) using data from The Health Improvement Network database. Thirty-day case fatality was stratified by age, sex, and calendar year after ICH and SAH using logistic regression. Cox proportional hazards regression analyses were used to estimate the risk of death during the first year of follow-up and survivors at 1 year. Case fatality after ICH was 42.0%, compared with 28.7% after SAH. It increased with age (ICH: 29.7% for 20-49 years, 54.6% for 80-89 years; SAH: 20.3% for 20-49 years, 56.7% for 80-89 years; both p-trend < 0.001), and decreased over the period 2000-2001 to 2006-2008 (ICH: from 53.1% to 35.8%, p-trend < 0.001; SAH: from 33.3% to 24.7%, p-trend = 0.02). Risk of death was significantly higher among stroke patients during the first year of follow-up compared with controls (ICH: hazard ratio [HR] 2.60, 95% confidence interval [CI] 2.09-3.24, p < 0.01; SAH: HR 2.87, 95% CI 2.07-3.97, p < 0.01) and remained elevated among survivors at 1 year (ICH: HR 2.02, 95% CI 1.75-2.32, p < 0.01; SAH: HR 1.32, 95% CI 1.02-1.69, p = 0.03). More than one-third of individuals die in the first month after hemorrhagic stroke, and patients younger than 50 years are more likely to die after ICH than SAH. Short-term case fatality has decreased over time. Patients who survive hemorrhagic stroke have a continuing elevated risk of death compared with matched individuals from the general population.

Overcoming the Challenges of Unstructured Data in Multi-site, Electronic Medical Record-based Abstraction

PubMed Central

Polnaszek, Brock; Gilmore-Bykovskyi, Andrea; Hovanes, Melissa; Roiland, Rachel; Ferguson, Patrick; Brown, Roger; Kind, Amy JH

2014-01-01

Background Unstructured data encountered during retrospective electronic medical record (EMR) abstraction has routinely been identified as challenging to reliably abstract, as this data is often recorded as free text, without limitations to format or structure. There is increased interest in reliably abstracting this type of data given its prominent role in care coordination and communication, yet limited methodological guidance exists. Objective As standard abstraction approaches resulted in sub-standard data reliability for unstructured data elements collected as part of a multi-site, retrospective EMR study of hospital discharge communication quality, our goal was to develop, apply and examine the utility of a phase-based approach to reliably abstract unstructured data. This approach is examined using the specific example of discharge communication for warfarin management. Research Design We adopted a “fit-for-use” framework to guide the development and evaluation of abstraction methods using a four step, phase-based approach including (1) team building, (2) identification of challenges, (3) adaptation of abstraction methods, and (4) systematic data quality monitoring. Measures Unstructured data elements were the focus of this study, including elements communicating steps in warfarin management (e.g., warfarin initiation) and medical follow-up (e.g., timeframe for follow-up). Results After implementation of the phase-based approach, inter-rater reliability for all unstructured data elements demonstrated kappas of ≥ 0.89 -- an average increase of + 0.25 for each unstructured data element. Conclusions As compared to standard abstraction methodologies, this phase-based approach was more time intensive, but did markedly increase abstraction reliability for unstructured data elements within multi-site EMR documentation. PMID:27624585

Penetrance of Hemochromatosis in HFE Genotypes Resulting in p.Cys282Tyr and p.[Cys282Tyr];[His63Asp] in the eMERGE Network

PubMed Central

Gallego, Carlos J.; Burt, Amber; Sundaresan, Agnes S.; Ye, Zi; Shaw, Christopher; Crosslin, David R.; Crane, Paul K.; Fullerton, S. Malia; Hansen, Kris; Carrell, David; Kuivaniemi, Helena; Derr, Kimberly; de Andrade, Mariza; McCarty, Catherine A.; Kitchner, Terrie E.; Ragon, Brittany K.; Stallings, Sarah C.; Papa, Gabriella; Bochenek, Joseph; Smith, Maureen E.; Aufox, Sharon A.; Pacheco, Jennifer A.; Patel, Vaibhav; Friesema, Elisha M.; Erwin, Angelika Ludtke; Gottesman, Omri; Gerhard, Glenn S.; Ritchie, Marylyn; Motulsky, Arno G.; Kullo, Iftikhar J.; Larson, Eric B.; Tromp, Gerard; Brilliant, Murray H.; Bottinger, Erwin; Denny, Joshua C.; Roden, Dan M.; Williams, Marc S.; Jarvik, Gail P.

2015-01-01

Hereditary hemochromatosis (HH) is a common autosomal-recessive disorder associated with pathogenic HFE variants, most commonly those resulting in p.Cys282Tyr and p.His63Asp. Recommendations on returning incidental findings of HFE variants in individuals undergoing genome-scale sequencing should be informed by penetrance estimates of HH in unselected samples. We used the eMERGE Network, a multicenter cohort with genotype data linked to electronic medical records, to estimate the diagnostic rate and clinical penetrance of HH in 98 individuals homozygous for the variant coding for HFE p.Cys282Tyr and 397 compound heterozygotes with variants resulting in p.[His63Asp];[Cys282Tyr]. The diagnostic rate of HH in males was 24.4% for p.Cys282Tyr homozygotes and 3.5% for compound heterozygotes (p < 0.001); in females, it was 14.0% for p.Cys282Tyr homozygotes and 2.3% for compound heterozygotes (p < 0.001). Only males showed differences across genotypes in transferrin saturation levels (100% of homozygotes versus 37.5% of compound heterozygotes with transferrin saturation > 50%; p = 0.003), serum ferritin levels (77.8% versus 33.3% with serum ferritin > 300 ng/ml; p = 0.006), and diabetes (44.7% versus 28.0%; p = 0.03). No differences were found in the prevalence of heart disease, arthritis, or liver disease, except for the rate of liver biopsy (10.9% versus 1.8% [p = 0.013] in males; 9.1% versus 2% [p = 0.035] in females). Given the higher rate of HH diagnosis than in prior studies, the high penetrance of iron overload, and the frequency of at-risk genotypes, in addition to other suggested actionable adult-onset genetic conditions, opportunistic screening should be considered for p.[Cys282Tyr];[Cys282Tyr] individuals with existing genomic data. PMID:26365338

Investigating the Use of Frequency Selective Surfaces in High Power Microwave Applications

DTIC Science & Technology

2010-03-01

radar applications were proving useful during World War II. Both allies and enemies were busy figuring out how to obtain, classify and use returns from...where the powers that are entering and leaving the network are represented by P in = 1 2 [a1a ∗ 1 + a2a ∗ 2] , (3.3) P out = 1 2 [b1b ∗ 1 + b2b ∗ 2

p53 prevents progression of nevi to melanoma predominantly through cell cycle regulation

PubMed Central

Terzian, Tamara; Torchia, Enrique C.; Dai, Daisy; Robinson, Steven E.; Murao, Kazutoshi; Stiegmann, Regan A.; Gonzalez, Victoria; Boyle, Glen M.; Powell, Marianne B.; Pollock, Pamela M.; Lozano, Guillermina; Robinson, William A.; Roop, Dennis R.; Box, Neil F.

2011-01-01

p53 is the central member of a critical tumor suppressor pathway in virtually all tumor types, where it is silenced mainly by missense mutations. In melanoma, p53 predominantly remains wild type, thus its role has been neglected. To study the effect of p53 on melanocyte function and melanomagenesis, we crossed the ‘high-p53’ Mdm4+/− mouse to the well-established TP-ras0/+ murine melanoma progression model. After treatment with the carcinogen dimethylbenzanthracene (DMBA), TP-ras0/+ mice on the Mdm4+/− background developed fewer tumors with a delay in the age of onset of melanomas compared to TP-ras0/+ mice. Furthermore, we observed a dramatic decrease in tumor growth, lack of metastasis with increased survival of TP-ras0/+: Mdm4+/− mice. Thus, p53 effectively prevented the conversion of small benign tumors to malignant and metastatic melanoma. p53 activation in cultured primary melanocyte and melanoma cell lines using Nutlin-3, a specific Mdm2 antagonist, supported these findings. Moreover, global gene expression and network analysis of Nutlin-3-treated primary human melanocytes indicated that cell cycle regulation through the p21WAF1/CIP1 signaling network may be the key anti-melanomagenic activity of p53. PMID:20849464

FoxP2 in songbirds.

PubMed

Wohlgemuth, Sandra; Adam, Iris; Scharff, Constance

2014-10-01

Humans with mutations in the transcription factor FOXP2 display a severe speech disorder. Songbirds are a powerful model system to study FoxP2. Like humans, songbirds communicate via vocalizations that are imitatively learned during critical periods and this learning is influenced by social factors and relies on functionally lateralized neural circuits. During the past five years significant progress has been made moving from a descriptive to a more mechanistic understanding of how FoxP2 functions in songbirds. Current evidence from molecular and electrophysiological studies indicates that FoxP2 is important for shaping synaptic plasticity of specific neuron populations. One future goal will be to identify the transcriptional regulation orchestrated by FoxP2 and its associated molecular network that brings about these physiological effects. This will be key to further unravel how FoxP2 influences synaptic function and thereby contributes to auditory guided vocal motor behavior in the songbird model. Copyright © 2014 Elsevier Ltd. All rights reserved.

P-glycoprotein (ABCB1) inhibited network of mitochondrion transport along microtubule and BMP signal-induced cell shape in chimpanzee left cerebrum by systems-theoretical analysis.

PubMed

Lin, Hong; Wang, Lin; Jiang, Minghu; Huang, Juxiang; Qi, Lianxiu

2012-10-01

We constructed the significant low-expression P-glycoprotein (ABCB1) inhibited transport and signal network in chimpanzee compared with high-expression (fold change ≥2) the human left cerebrum in GEO data set, by using integration of gene regulatory activated and inhibited network inference method with gene ontology (GO) analysis. Our result showed that ABCB1 transport and signal upstream network RAB2A inhibited ABCB1, and downstream ABCB1-inhibited SMAD1_2, NCK2, SLC25A46, GDF10, RASGRP1, EGFR, LRPPRC, RASSF2, RASA4, CA2, CBLB, UBR5, SLC25A16, ITGB3BP, DDIT4, PDPN, RAB2A in chimpanzee left cerebrum. We obtained that the different biological processes of ABCB1 inhibited transport and signal network repressed carbon dioxide transport, ER to Golgi vesicle-mediated transport, folic acid transport, mitochondrion transport along microtubule, water transport, BMP signaling pathway, Ras protein signal transduction, transforming growth factor beta receptor signaling pathway in chimpanzee compared with the inhibited network of the human left cerebrum, as a result of inducing inhibition of mitochondrion transport along microtubule and BMP signal-induced cell shape in chimpanzee left cerebrum. Our hypothesis was verified by the same and different biological processes of ABCB1 inhibited transport and signal network of chimpanzee compared with the corresponding activated network of chimpanzee and the human left cerebrum, respectively. Copyright © 2012 John Wiley & Sons, Ltd.

An advanced NMR protocol for the structural characterization of aluminophosphate glasses.

PubMed

van Wüllen, Leo; Tricot, Grégory; Wegner, Sebastian

2007-10-01

In this work a combination of complementary advanced solid-state nuclear magnetic resonance (NMR) strategies is employed to analyse the network organization in aluminophosphate glasses to an unprecedented level of detailed insight. The combined results from MAS, MQMAS and (31)P-{(27)Al}-CP-heteronuclear correlation spectroscopy (HETCOR) NMR experiments allow for a detailed speciation of the different phosphate and aluminate species present in the glass. The interconnection of these local building units to an extended three-dimensional network is explored employing heteronuclear dipolar and scalar NMR approaches to quantify P-O-Al connectivity by (31)P{(27)Al}-heteronuclear multiple quantum coherence (HMQC), -rotational echo adiabatic passage double resonance (REAPDOR) and -HETCOR NMR as well as (27)Al{(31)P}-rotational echo double resonance (REDOR) NMR experiments, complemented by (31)P-2D-J-RESolved MAS NMR experiments to probe P-O-P connectivity utilizing the through bond scalar J-coupling. The combination of the results from the various NMR approaches enables us to not only quantify the phosphate units present in the glass but also to identify their respective structural environments within the three-dimensional network on a medium length scale employing a modified Q notation, Q(n)(m),(AlO)(x), where n denotes the number of connected tetrahedral phosphate, m gives the number of aluminate species connected to a central phosphate unit and x specifies the nature of the bonded aluminate species (i.e. 4, 5 or 6 coordinate aluminium).

Regulatory interactions between long noncoding RNA LINC00968 and miR-9-3p in non-small cell lung cancer: A bioinformatic analysis based on miRNA microarray, GEO and TCGA.

PubMed

Li, Dong-Yao; Chen, Wen-Jie; Shang, Jun; Chen, Gang; Li, Shi-Kang

2018-06-01

Long non-coding RNAs (lncRNAs) have been demonstrated to mediate carcinogenesis in various types of cancer. However, the regulatory role of lncRNA LINC00968 in lung adenocarcinoma remains unclear. The microRNA (miRNA) expression in LINC00968-overexpressing human lung adenocarcinoma A549 cells was detected using miRNA microarray analysis. miR-9-3p was selected for further analysis, and its expression was verified in the Gene Expression Omnibus (GEO) database. In addition, the regulatory axis of LINC00968 was validated using The Cancer Genome Atlas (TCGA) database. Results of the GEO database indicated miR-9-3p expression in lung adenocarcinoma was significantly higher compared with normal tissues. Functional enrichment analyses of the target genes of miR-9-3p indicated protein binding and the AMP-activated protein kinase pathway were the most enriched Gene Ontology and KEGG terms, respectively. Combining target genes with the correlated genes of LINC00968 and miR-9-3p, 120 objective genes were obtained, which were used to construct a protein-protein interaction (PPI) network. Cyclin A2 (CCNA2) was identified to have a vital role in the PPI network. Significant correlations were detected between LINC00968, miR-9-3p and CCNA2 in lung adenocarcinoma. The LINC00968/miR-9-3p/CCNA2 regulatory axis provides a new foundation for further evaluating the regulatory mechanisms of LINC00968 in lung adenocarcinoma.

Network structure control of binary mixed langmuir monolayers of homo-PS and PS-b-P2VP.

PubMed

Wen, Gangyao

2010-03-25

Our recent work showed there existed a composition window for mixed Langmuir monolayers of homopolystyrene (h-PS) and a symmetric diblock copolymer polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) to form necklace-network structures at the air/water interface. In order to study further the possible mechanism and control the network structure (i.e., surface coverage and nanoaggregate diameter), effects of spreading solution concentration and volume, subphase temperature, and transfer pressure on the network structure were studied by the Langmuir monolayer technique and tapping mode atomic force microscopy. With the increase of transfer pressure, there existed a novel nonlinear behavior for the nanoaggregate diameter first to increase, then to decrease, and finally to increase again, while the surface coverage tended to increase step by step. Moreover, with the elevation of temperature, chain motion between the adjoining nanoaggregates tended to be improved and thus the nanoaggregate diameter tended to be more uniform.

PI(3,5)P2 controls endosomal branched actin dynamics by regulating cortactin–actin interactions

PubMed Central

Hong, Nan Hyung; Qi, Aidong

2015-01-01

Branched actin critically contributes to membrane trafficking by regulating membrane curvature, dynamics, fission, and transport. However, how actin dynamics are controlled at membranes is poorly understood. Here, we identify the branched actin regulator cortactin as a direct binding partner of phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) and demonstrate that their interaction promotes turnover of late endosomal actin. In vitro biochemical studies indicated that cortactin binds PI(3,5)P2 via its actin filament-binding region. Furthermore, PI(3,5)P2 competed with actin filaments for binding to cortactin, thereby antagonizing cortactin activity. These findings suggest that PI(3,5)P2 formation on endosomes may remove cortactin from endosome-associated branched actin. Indeed, inhibition of PI(3,5)P2 production led to cortactin accumulation and actin stabilization on Rab7+ endosomes. Conversely, inhibition of Arp2/3 complex activity greatly reduced cortactin localization to late endosomes. Knockdown of cortactin reversed PI(3,5)P2-inhibitor–induced actin accumulation and stabilization on endosomes. These data suggest a model in which PI(3,5)P2 binding removes cortactin from late endosomal branched actin networks and thereby promotes net actin turnover. PMID:26323691

Multigenic Control of Pod Shattering Resistance in Chinese Rapeseed Germplasm Revealed by Genome-Wide Association and Linkage Analyses

PubMed Central

Liu, Jia; Wang, Jun; Wang, Hui; Wang, Wenxiang; Zhou, Rijin; Mei, Desheng; Cheng, Hongtao; Yang, Juan; Raman, Harsh; Hu, Qiong

2016-01-01

The majority of rapeseed cultivars shatter seeds upon maturity especially under hot-dry and windy conditions, reducing yield and gross margin return to growers. Here, we identified quantitative trait loci (QTL) for resistance to pod shatter in an unstructured diverse panel of 143 rapeseed accessions, and two structured populations derived from bi-parental doubled haploid (DH) and inter-mated (IF2) crosses derived from R1 (resistant to pod shattering) and R2 (prone to pod shattering) accessions. Genome-wide association analysis identified six significant QTL for resistance to pod shatter located on chromosomes A01, A06, A07, A09, C02, and C05. Two of the QTL, qSRI.A09 delimited with the SNP marker Bn-A09-p30171993 (A09) and qSRI.A06 delimited with the SNP marker Bn-A06-p115948 (A06) could be repeatedly detected across environments in a diversity panel, DH and IF2 populations, suggesting that at least two loci on chromosomes A06 and A09 were the main contributors to pod shatter resistance in Chinese germplasm. Significant SNP markers identified in this study especially those that appeared repeatedly across environments provide a cost-effective and an efficient method for introgression and pyramiding of favorable alleles for pod shatter resistance via marker-assisted selection in rapeseed improvement programs. PMID:27493651

Effect of Prevascularization on In Vivo Vascularization of Poly(Propylene fumarate)/Fibrin Scaffolds

PubMed Central

Mishra, Ruchi; Roux, Brianna M.; Posukonis, Megan; Bodamer, Emily; Brey, Eric M.; Fisher, John P.; Dean, David

2016-01-01

The importance of vascularization in the field of bone tissue engineering has been established by previous studies. The present work proposes a novel poly(propylene fumarate) (PPF)/fibrin composite scaffold for the development of vascularized neobone tissue. The effect of prevascularization (i.e., in vitro pre-culture prior to implantation) with human mesenchymal stem cells (hMSCs) and human umbilical vein endothelial cells (HUVECs) on in vivo vascularization of scaffolds was determined. Five conditions were studied: no pre-culture (NP), 1 week preculture (1P), 2 week pre-culture (2P), 3 week pre-culture (3P), and scaffolds without cells (control, C). Scaffolds were implanted subcutaneously in a severe combined immunodeficiency (SCID) mice model for 9 days. During in vitro studies, CD31 staining showed a significant increase in vascular network area over 3 weeks of culture. Vascular density was significantly higher in vivo when comparing NP to 3P groups. Immunohistochemical staining of human CD-31 expression indicated spreading of vascular networks with increasing pre-culture time. These vascular networks were perfused with mouse blood indicated by perfused lectin staining in human CD-31 positive vessels. Our results demonstrate that in vitro prevascularization supports in vivo vascularization in PPF/fibrin scaffolds. PMID:26606451

Design of a Mobile Agent-Based Adaptive Communication Middleware for Federations of Critical Infrastructure Simulations

NASA Astrophysics Data System (ADS)

Görbil, Gökçe; Gelenbe, Erol

The simulation of critical infrastructures (CI) can involve the use of diverse domain specific simulators that run on geographically distant sites. These diverse simulators must then be coordinated to run concurrently in order to evaluate the performance of critical infrastructures which influence each other, especially in emergency or resource-critical situations. We therefore describe the design of an adaptive communication middleware that provides reliable and real-time one-to-one and group communications for federations of CI simulators over a wide-area network (WAN). The proposed middleware is composed of mobile agent-based peer-to-peer (P2P) overlays, called virtual networks (VNets), to enable resilient, adaptive and real-time communications over unreliable and dynamic physical networks (PNets). The autonomous software agents comprising the communication middleware monitor their performance and the underlying PNet, and dynamically adapt the P2P overlay and migrate over the PNet in order to optimize communications according to the requirements of the federation and the current conditions of the PNet. Reliable communications is provided via redundancy within the communication middleware and intelligent migration of agents over the PNet. The proposed middleware integrates security methods in order to protect the communication infrastructure against attacks and provide privacy and anonymity to the participants of the federation. Experiments with an initial version of the communication middleware over a real-life networking testbed show that promising improvements can be obtained for unicast and group communications via the agent migration capability of our middleware.

Scalable direct Vlasov solver with discontinuous Galerkin method on unstructured mesh.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, J.; Ostroumov, P. N.; Mustapha, B.

2010-12-01

This paper presents the development of parallel direct Vlasov solvers with discontinuous Galerkin (DG) method for beam and plasma simulations in four dimensions. Both physical and velocity spaces are in two dimesions (2P2V) with unstructured mesh. Contrary to the standard particle-in-cell (PIC) approach for kinetic space plasma simulations, i.e., solving Vlasov-Maxwell equations, direct method has been used in this paper. There are several benefits to solving a Vlasov equation directly, such as avoiding noise associated with a finite number of particles and the capability to capture fine structure in the plasma. The most challanging part of a direct Vlasov solvermore » comes from higher dimensions, as the computational cost increases as N{sup 2d}, where d is the dimension of the physical space. Recently, due to the fast development of supercomputers, the possibility has become more realistic. Many efforts have been made to solve Vlasov equations in low dimensions before; now more interest has focused on higher dimensions. Different numerical methods have been tried so far, such as the finite difference method, Fourier Spectral method, finite volume method, and spectral element method. This paper is based on our previous efforts to use the DG method. The DG method has been proven to be very successful in solving Maxwell equations, and this paper is our first effort in applying the DG method to Vlasov equations. DG has shown several advantages, such as local mass matrix, strong stability, and easy parallelization. These are particularly suitable for Vlasov equations. Domain decomposition in high dimensions has been used for parallelization; these include a highly scalable parallel two-dimensional Poisson solver. Benchmark results have been shown and simulation results will be reported.« less

Reversible Aggregation Plays a Crucial Role on the Folding Landscape of p53 Core Domain

PubMed Central

Ishimaru, Daniella; Lima, Luis M. T. R.; Maia, Lenize F.; Lopez, Priscila M.; Ano Bom, Ana P.; Valente, Ana P.; Silva, Jerson L.

2004-01-01

The role of tumor suppressor protein p53 in cell cycle control depends on its flexible and partially unstructured conformation, which makes it crucial to understand its folding landscape. Here we report an intermediate structure of the core domain of the tumor suppressor protein p53 (p53C) during equilibrium and kinetic folding/unfolding transitions induced by guanidinium chloride. This partially folded structure was undetectable when investigated by intrinsic fluorescence. Indeed, the fluorescence data showed a simple two-state transition. On the other hand, analysis of far ultraviolet circular dichroism in 1.0 M guanidinium chloride demonstrated a high content of secondary structure, and the use of an extrinsic fluorescent probe, 4,4′-dianilino-1,1′ binaphthyl-5,5′-disulfonic acid, indicated an increase in exposure of the hydrophobic core at 1 M guanidinium chloride. This partially folded conformation of p53C was plagued by aggregation, as suggested by one-dimensional NMR and demonstrated by light-scattering and gel-filtration chromatography. Dissociation by high pressure of these aggregates reveals the reversibility of the process and that the aggregates have water-excluded cavities. Kinetic measurements show that the intermediate formed in a parallel reaction between unfolded and folded structures and that it is under fine energetic control. They are not only crucial to the folding pathway of p53C but may explain as well the vulnerability of p53C to undergo departure of the native to an inactive state, which makes the cell susceptible to malignant transformation. PMID:15298872

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burke, Timothy P.; Martz, Roger L.; Kiedrowski, Brian C.

New unstructured mesh capabilities in MCNP6 (developmental version during summer 2012) show potential for conducting multi-physics analyses by coupling MCNP to a finite element solver such as Abaqus/CAE[2]. Before these new capabilities can be utilized, the ability of MCNP to accurately estimate eigenvalues and pin powers using an unstructured mesh must first be verified. Previous work to verify the unstructured mesh capabilities in MCNP was accomplished using the Godiva sphere [1], and this work attempts to build on that. To accomplish this, a criticality benchmark and a fuel assembly benchmark were used for calculations in MCNP using both the Constructivemore » Solid Geometry (CSG) native to MCNP and the unstructured mesh geometry generated using Abaqus/CAE. The Big Ten criticality benchmark [3] was modeled due to its geometry being similar to that of a reactor fuel pin. The C5G7 3-D Mixed Oxide (MOX) Fuel Assembly Benchmark [4] was modeled to test the unstructured mesh capabilities on a reactor-type problem.« less

Two-Dimensional Metal-Free Organic Multiferroic Material for Design of Multifunctional Integrated Circuits.

PubMed

Tu, Zhengyuan; Wu, Menghao; Zeng, Xiao Cheng

2017-05-04

Coexistence of ferromagnetism and ferroelectricity in a single 2D material is highly desirable for integration of multifunctional units in 2D material-based circuits. We report theoretical evidence of C 6 N 8 H organic network as being the first 2D organic multiferroic material with coexisting ferromagnetic and ferroelectric properties. The ferroelectricity stems from multimode proton-transfer within the 2D C 6 N 8 H network, in which a long-range proton-transfer mode is enabled by the facilitation of oxygen molecule when the network is exposed to the air. Such oxygen-assisted ferroelectricity also leads to a high Curie temperature and coupling between ferroelectricity and ferromagnetism. We also find that hydrogenation and carbon doping can transform the 2D g-C 3 N 4 network from an insulator to an n-type/p-type magnetic semiconductor with modest bandgap. Akin to the dopant induced n/p channels in silicon wafer, a variety of dopant created functional units can be integrated into the g-C 3 N 4 wafer by design for nanoelectronic applications.

Relationship between feeding practices and weanling diarrhoea in northeast Thailand.

PubMed

Cao, X; Rawalai, K; Thompson, A J; Hartel, G; Thompson, S; Paterson, J H; Chusilp, K

2000-09-01

Diarrhoea is a major public health problem in Thailand. During November 1998-January 1999, a cross-sectional survey and a nested qualitative study were conducted to understand the relationship between feeding practices and weanling diarrhoea, and to describe the related local beliefs and practices in a subdistrict of northeast Thailand. A cluster-sampling method was used for selecting 156 weanlings aged 3-24 months. A structured interview was conducted with the main caregivers of these weanlings. The questionnaire used for the interview included items about feeding practices and diarrhoea-history of the weanlings in 2 months prior to the interview. Seven focus-group discussions with an opportunistic sample of the caregivers were held in the villages. A series of vignettes and unstructured questions were used for eliciting the local beliefs about weanling diarrhoea and its causes. Thirty-six (23%) of the 156 weanlings had diarrhoea in 2 months prior to the interview. The factors that were significantly related to reported weanling diarrhoea included consumption of unboiled water by weanlings (OR = 10, p = 0.03), not covering perishable foods (OR = 3, p = 0.02), and washing feeding utensils of weanlings without dishwashing detergent (OR = 3.1, p = 0.02), 'Su' and 'tongsia'--two common local terms--were used for describing different types of weanling diarrhoea. Many caregivers considered 'su' a natural occurrence in a child's development. The results suggest that some poor feeding practices may contribute to the higher risk of weanling diarrhoea in northeast Thailand. Some local beliefs about weanling diarrhoea may mask the true causes, and mislead messages about its prevention.

pH induced contrast in viscoelasticity imaging of biopolymers

PubMed Central

Yapp, R D; Insana, M F

2009-01-01

Understanding contrast mechanisms and identifying discriminating features is at the heart of diagnostic imaging development. This report focuses on how pH influences the viscoelastic properties of biopolymers to better understand the effects of extracellular pH on breast tumour elasticity imaging. Extracellular pH is known to decrease as much as 1 pH unit in breast tumours, thus creating a dangerous environment that increases cellular mutatation rates and therapeutic resistance. We used a gelatin hydrogel phantom to isolate the effects of pH on a polymer network with similarities to the extracellular matrix in breast stroma. Using compressive unconfined creep and stress relaxation measurements, we systematically measured the viscoelastic features sensitive to pH by way of time domain models and complex modulus analysis. These results are used to determine the sensitivity of quasi-static ultrasonic elasticity imaging to pH. We found a strong elastic response of the polymer network to pH, such that the matrix stiffness decreases as pH was reduced, however the viscous response of the medium to pH was negligible. While physiological features of breast stroma such as proteoglycans and vascular networks are not included in our hydrogel model, observations in this study provide insight into viscoelastic features specific to pH changes in the collagenous stromal network. These observations suggest that the large contrast common in breast tumours with desmoplasia may be reduced under acidic conditions, and that viscoelastic features are unlikely to improve discriminability. PMID:19174599

SYNTHESIS AND IN VITRO CHARACTERIZATION OF HYDROXYPROPYL METHYLCELLULOSE-GRAFT-POLY (ACRYLIC ACID/2-ACRYLAMIDO-2-METHYL-1-PROPANESULFONIC ACID) POLYMERIC NETWORK FOR CONTROLLED RELEASE OF CAPTOPRIL.

PubMed

Furqan Muhammad, Iqbal; Mahmood, Ahmad; Aysha, Rashid

2016-01-01

A super-absorbent hydrogel was developed by crosslinking of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and acrylic acid with hydroxypropyl methylcellulose (HPMC) for controlled release drug delivery of captopril, a well known antihypertensive drug. Acrylic acid and AMPS were polymerized and crosslinked with HPMC by free radical polymerization, a widely used chemical crosslinking method. N,N'-methylenebisacrylamide (MBA) and potassium persulfate (KPS) were added as cross-linker and initiator, respectively. The hydrogel formulation was loaded with captopril (as model drug). The concentration of captopril was monitored at 205 nm using UV spectrophotometer. Equilibrium swelling ratio was determined at pH 2, 4.5 and 7.4 to evaluate the pH responsiveness of the formed hydrogel. The super-absorbent hydrogels were evaluated by FTIR, SEM, XRD, and thermal analysis (DSC and TGA). The formation of new copolymeric network was determined by FTIR, XRD, TGA and DSC analysis. The hydrogel formulations with acrylic acid and AMPS ratio of 4: 1 and lower amounts of crosslinker had shown maximum swelling. Moreover, higher release rate of captopril was observed at pH 7.4 than at pH 2, because of more swelling capacity of copolymer with increasing pH of the aqueous medium. The present research work confirms the development of a stable hydrogel comprising of HPMC with acrylic acid and AMPS. The prepared hydrogels exhibited pH sensitive behav-ior. This superabsorbent composite prepared could be a successful drug carrier for treating hypertension.

Management Information Systems and the Age of Social Media: An Investigation of Social Network Research

DTIC Science & Technology

2013-03-01

Sunil 2 0.58 2 2 6.58 Agarwal, Ritu 2 0.83 1 1.7 5.53 Wonseok Oh 2 0.66 1 1.7 5.36 Clemons, Eric K. 1 1 1 1.5 4.5 19 Melville, Nigel P. 1 1 1...receiving the highest score. Lionel P. Robert, Jr. and Sunil Wattal were second and third, respectively. Affiliation productivity was determined

Convergent genetic and expression data implicate immunity in Alzheimer's disease

PubMed Central

Jones, Lesley; Lambert, Jean-Charles; Wang, Li-San; Choi, Seung-Hoan; Harold, Denise; Vedernikov, Alexey; Escott-Price, Valentina; Stone, Timothy; Richards, Alexander; Bellenguez, Céline; Ibrahim-Verbaas, Carla A; Naj, Adam C; Sims, Rebecca; Gerrish, Amy; Jun, Gyungah; DeStefano, Anita L; Bis, Joshua C; Beecham, Gary W; Grenier-Boley, Benjamin; Russo, Giancarlo; Thornton-Wells, Tricia A; Jones, Nicola; Smith, Albert V; Chouraki, Vincent; Thomas, Charlene; Ikram, M Arfan; Zelenika, Diana; Vardarajan, Badri N; Kamatani, Yoichiro; Lin, Chiao-Feng; Schmidt, Helena; Kunkle, Brian; Dunstan, Melanie L; Ruiz, Agustin; Bihoreau, Marie-Thérèse; Reitz, Christiane; Pasquier, Florence; Hollingworth, Paul; Hanon, Olivier; Fitzpatrick, Annette L; Buxbaum, Joseph D; Campion, Dominique; Crane, Paul K; Becker, Tim; Gudnason, Vilmundur; Cruchaga, Carlos; Craig, David; Amin, Najaf; Berr, Claudine; Lopez, Oscar L; De Jager, Philip L; Deramecourt, Vincent; Johnston, Janet A; Evans, Denis; Lovestone, Simon; Letteneur, Luc; Kornhuber, Johanes; Tárraga, Lluís; Rubinsztein, David C; Eiriksdottir, Gudny; Sleegers, Kristel; Goate, Alison M; Fiévet, Nathalie; Huentelman, Matthew J; Gill, Michael; Emilsson, Valur; Brown, Kristelle; Kamboh, M Ilyas; Keller, Lina; Barberger-Gateau, Pascale; McGuinness, Bernadette; Larson, Eric B; Myers, Amanda J; Dufouil, Carole; Todd, Stephen; Wallon, David; Love, Seth; Kehoe, Pat; Rogaeva, Ekaterina; Gallacher, John; George-Hyslop, Peter St; Clarimon, Jordi; Lleὀ, Alberti; Bayer, Anthony; Tsuang, Debby W; Yu, Lei; Tsolaki, Magda; Bossù, Paola; Spalletta, Gianfranco; Proitsi, Petra; Collinge, John; Sorbi, Sandro; Garcia, Florentino Sanchez; Fox, Nick; Hardy, John; Naranjo, Maria Candida Deniz; Razquin, Cristina; Bosco, Paola; Clarke, Robert; Brayne, Carol; Galimberti, Daniela; Mancuso, Michelangelo; Moebus, Susanne; Mecocci, Patrizia; del Zompo, Maria; Maier, Wolfgang; Hampel, Harald; Pilotto, Alberto; Bullido, Maria; Panza, Francesco; Caffarra, Paolo; Nacmias, Benedetta; Gilbert, John R; Mayhaus, Manuel; Jessen, Frank; Dichgans, Martin; Lannfelt, Lars; Hakonarson, Hakon; Pichler, Sabrina; Carrasquillo, Minerva M; Ingelsson, Martin; Beekly, Duane; Alavarez, Victoria; Zou, Fanggeng; Valladares, Otto; Younkin, Steven G; Coto, Eliecer; Hamilton-Nelson, Kara L; Mateo, Ignacio; Owen, Michael J; Faber, Kelley M; Jonsson, Palmi V; Combarros, Onofre; O'Donovan, Michael C; Cantwell, Laura B; Soininen, Hilkka; Blacker, Deborah; Mead, Simon; Mosley, Thomas H; Bennett, David A; Harris, Tamara B; Fratiglioni, Laura; Holmes, Clive; de Bruijn, Renee FAG; Passmore, Peter; Montine, Thomas J; Bettens, Karolien; Rotter, Jerome I; Brice, Alexis; Morgan, Kevin; Foroud, Tatiana M; Kukull, Walter A; Hannequin, Didier; Powell, John F; Nalls, Michael A; Ritchie, Karen; Lunetta, Kathryn L; Kauwe, John SK; Boerwinkle, Eric; Riemenschneider, Matthias; Boada, Mercè; Hiltunen, Mikko; Martin, Eden R; Pastor, Pau; Schmidt, Reinhold; Rujescu, Dan; Dartigues, Jean-François; Mayeux, Richard; Tzourio, Christophe; Hofman, Albert; Nöthen, Markus M; Graff, Caroline; Psaty, Bruce M; Haines, Jonathan L; Lathrop, Mark; Pericak-Vance, Margaret A; Launer, Lenore J; Farrer, Lindsay A; van Duijn, Cornelia M; Van Broekhoven, Christine; Ramirez, Alfredo; Schellenberg, Gerard D; Seshadri, Sudha; Amouyel, Philippe; Holmans, Peter A

2015-01-01

Background Late–onset Alzheimer's disease (AD) is heritable with 20 genes showing genome wide association in the International Genomics of Alzheimer's Project (IGAP). To identify the biology underlying the disease we extended these genetic data in a pathway analysis. Methods The ALIGATOR and GSEA algorithms were used in the IGAP data to identify associated functional pathways and correlated gene expression networks in human brain. Results ALIGATOR identified an excess of curated biological pathways showing enrichment of association. Enriched areas of biology included the immune response (p = 3.27×10-12 after multiple testing correction for pathways), regulation of endocytosis (p = 1.31×10-11), cholesterol transport (p = 2.96 × 10-9) and proteasome-ubiquitin activity (p = 1.34×10-6). Correlated gene expression analysis identified four significant network modules, all related to the immune response (corrected p 0.002 – 0.05). Conclusions The immune response, regulation of endocytosis, cholesterol transport and protein ubiquitination represent prime targets for AD therapeutics. PMID:25533204

Convergent genetic and expression data implicate immunity in Alzheimer's disease.

PubMed

2015-06-01

Late-onset Alzheimer's disease (AD) is heritable with 20 genes showing genome-wide association in the International Genomics of Alzheimer's Project (IGAP). To identify the biology underlying the disease, we extended these genetic data in a pathway analysis. The ALIGATOR and GSEA algorithms were used in the IGAP data to identify associated functional pathways and correlated gene expression networks in human brain. ALIGATOR identified an excess of curated biological pathways showing enrichment of association. Enriched areas of biology included the immune response (P = 3.27 × 10(-12) after multiple testing correction for pathways), regulation of endocytosis (P = 1.31 × 10(-11)), cholesterol transport (P = 2.96 × 10(-9)), and proteasome-ubiquitin activity (P = 1.34 × 10(-6)). Correlated gene expression analysis identified four significant network modules, all related to the immune response (corrected P = .002-.05). The immune response, regulation of endocytosis, cholesterol transport, and protein ubiquitination represent prime targets for AD therapeutics. Copyright © 2015. Published by Elsevier Inc.

Child pornography possessors: trends in offender and case characteristics.

PubMed

Wolak, Janis; Finkelhor, David; Mitchell, Kimberly

2011-03-01

This article describes trends in child pornography (CP) possession cases that ended in arrest in 2000 and in 2006, using data from the National Juvenile Online Victimization Study, a two-wave longitudinal survey of a national sample of more than 2,500 U.S. law enforcement agencies. In 2006, there were an estimated 3,672 arrests for CP possession, compared with 1,713 arrests in 2000. Many characteristics of the offenders and the offense remained stable. In both 2006 and 2000, most offenders were White, non-Hispanic males and socioeconomically diverse. Few were known to have committed previous sex crimes. Most had CP that depicted preteen children and serious sexual abuse. In 2006, however, a higher proportion of offenders were aged 18 to 25 years, used peer-to-peer (p2p) networks, had images of children younger than 3 years, and had CP videos. P2p users had more extreme images (e.g., younger victims, sexual violence) and larger numbers of images than those who did not use p2p networks. Findings reflect heightened efforts in the criminal justice system to combat CP crimes. More cases originated with investigations of CP possession and involved proactive investigations aimed at detecting CP. The great majority of cases were successfully prosecuted, with more offenders sentenced to incarceration and serving longer sentences than in 2000. As in 2000, one in six cases that began with investigations of CP possession detected offenders who had molested children.

The association between social network factors and mental health at different life stages.

PubMed

Levula, Andrew; Wilson, Andrew; Harré, Michael

2016-07-01

Psychosocial factors are important determinants of an individual's health. This study examines the association between health scores and social network factors on mental health across different life stages. Data were drawn from the Household Income and Labour Dynamics in Australia survey for adolescents (n = 1739), adults (n = 10,309) and seniors (n = 2287). Hierarchical regression modelling was applied to examine effects within and across age groups. All the variables were derived from the self-completion questionnaire. The social network factors were statistically significant predictors of mental health outcomes for all three life stages. For adolescents, the three social network factors were statistically significant with social isolation having the largest impact (β = -.284, p < .001), followed by social connection (β = .084, p < .001) and social trust having a similar effect (β = .073, p < .001). For adults social isolation had the highest impact (β = -.203, p < .001), followed by social connection (β = .110, p < .001) and social trust (β = .087, p < .001).The results for seniors were social isolation (β = -.188, p < .001), social connection (β = .147, p < .001) and social trust (β = .032, p < .05). After adding the social network factors, the models improved significantly with social isolation playing the most significant role across all life stages, whereas the other social network factors played a differentiated role depending upon the life stage. These findings have practical implications in the design of mental health interventions across different life stages.

Recurrent Network models of sequence generation and memory

PubMed Central

Rajan, Kanaka; Harvey, Christopher D; Tank, David W

2016-01-01

SUMMARY Sequential activation of neurons is a common feature of network activity during a variety of behaviors, including working memory and decision making. Previous network models for sequences and memory emphasized specialized architectures in which a principled mechanism is pre-wired into their connectivity. Here, we demonstrate that starting from random connectivity and modifying a small fraction of connections, a largely disordered recurrent network can produce sequences and implement working memory efficiently. We use this process, called Partial In-Network training (PINning), to model and match cellular-resolution imaging data from the posterior parietal cortex during a virtual memory-guided two-alternative forced choice task [Harvey, Coen and Tank, 2012]. Analysis of the connectivity reveals that sequences propagate by the cooperation between recurrent synaptic interactions and external inputs, rather than through feedforward or asymmetric connections. Together our results suggest that neural sequences may emerge through learning from largely unstructured network architectures. PMID:26971945

P2 receptor signaling in neurons and glial cells of the central nervous system.

PubMed

Köles, Laszlo; Leichsenring, Anna; Rubini, Patrizia; Illes, Peter

2011-01-01

Purine and pyrimidine nucleotides are extracellular signaling molecules in the central nervous system (CNS) leaving the intracellular space of various CNS cell types via nonexocytotic mechanisms. In addition, ATP is a neuro-and gliotransmitter released by exocytosis from neurons and neuroglia. These nucleotides activate P2 receptors of the P2X (ligand-gated cationic channels) and P2Y (G protein-coupled receptors) types. In mammalians, seven P2X and eight P2Y receptor subunits occur; three P2X subtypes form homomeric or heteromeric P2X receptors. P2Y subtypes may also hetero-oligomerize with each other as well as with other G protein-coupled receptors. P2X receptors are able to physically associate with various types of ligand-gated ion channels and thereby to interact with them. The P2 receptor homomers or heteromers exhibit specific sensitivities against pharmacological ligands and have preferential functional roles. They may be situated at both presynaptic (nerve terminals) and postsynaptic (somatodendritic) sites of neurons, where they modulate either transmitter release or the postsynaptic sensitivity to neurotransmitters. P2 receptors exist at neuroglia (e.g., astrocytes, oligodendrocytes) and microglia in the CNS. The neuroglial P2 receptors subserve the neuron-glia cross talk especially via their end-feets projecting to neighboring synapses. In addition, glial networks are able to communicate through coordinated oscillations of their intracellular Ca(2+) over considerable distances. P2 receptors are involved in the physiological regulation of CNS functions as well as in its pathophysiological dysregulation. Normal (motivation, reward, embryonic and postnatal development, neuroregeneration) and abnormal regulatory mechanisms (pain, neuroinflammation, neurodegeneration, epilepsy) are important examples for the significance of P2 receptor-mediated/modulated processes. Copyright © 2011 Elsevier Inc. All rights reserved.

Light Regulation of Swarming Motility in Pseudomonas syringae Integrates Signaling Pathways Mediated by a Bacteriophytochrome and a LOV Protein

PubMed Central

Wu, Liang; McGrane, Regina S.; Beattie, Gwyn A.

2013-01-01

ABSTRACT The biological and regulatory roles of photosensory proteins are poorly understood for nonphotosynthetic bacteria. The foliar bacterial pathogen Pseudomonas syringae has three photosensory protein-encoding genes that are predicted to encode the blue-light-sensing LOV (light, oxygen, or voltage) histidine kinase (LOV-HK) and two red/far-red-light-sensing bacteriophytochromes, BphP1 and BphP2. We provide evidence that LOV-HK and BphP1 form an integrated network that regulates swarming motility in response to multiple light wavelengths. The swarming motility of P. syringae B728a deletion mutants indicated that LOV-HK positively regulates swarming motility in response to blue light and BphP1 negatively regulates swarming motility in response to red and far-red light. BphP2 does not detectably regulate swarming motility. The histidine kinase activity of each LOV-HK and BphP1 is required for this regulation based on the loss of complementation upon mutation of residues key to their kinase activity. Surprisingly, mutants lacking both lov and bphP1 were similar in motility to a bphP1 single mutant in blue light, indicating that the loss of bphP1 is epistatic to the loss of lov and also that BphP1 unexpectedly responds to blue light. Moreover, whereas expression of bphP1 did not alter motility under blue light in a bphP1 mutant, it reduced motility in a mutant lacking lov and bphP1, demonstrating that LOV-HK positively regulates motility by suppressing negative regulation by BphP1. These results are the first to show cross talk between the LOV protein and phytochrome signaling pathways in bacteria, and the similarity of this regulatory network to that of photoreceptors in plants suggests a possible common ancestry. PMID:23760465

Metabolic Networks Integrative Cardiac Health Project (ICHP) - Center of Excellence

DTIC Science & Technology

2016-04-01

2.6; P = 0.001) among all variables, as the most significant predictor of abnormal CIMT, thus increasing risk for CVD. Conclusions: The Integrative ...1 Award Number: W81XWH-11-2-0227 TITLE: "Metabolic Networks Integrative Cardiac Health Project (ICHP) - Center of Excellence." PRINCIPAL...April 2016 2. REPORT TYPE ANNUAL 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE "Metabolic Networks Integrative Cardiac Health Project (ICHP

Ionizing radiation in the field of hydrogels used for agriculture and medicine

NASA Astrophysics Data System (ADS)

Radoiu, M.; Martin, D.; Oproiu, C.; Toma, M.; Popescu, A. S.; Bestea, V.; Dragusin, M.; Moraru, R.; Calinescu, I.; Manea, A.

1999-01-01

Some hydrogel types, obtained by gamma ray and electron beam irradiation, such as homopolymers of acrylamide (pAA type), co-polymers of acrylamide and sodium acrylate (pAANA type), homo-polymers of sodium acrylate (pNA type) and homo-polymers of 2-hydroxyethylmethacrylate (pHEMA type), are presented. The effects of the solution's chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of pAA, pAANA, pNA types are discussed. For the pHEMA type, which are reinforced in the polyester network, the studies concerning the influence of the irradiation parameters and chemical composition upon the shape stability after swelling and surface's roughness are also discussed.

The role of social networking web sites in influencing residency decisions.

PubMed

Schweitzer, Justin; Hannan, Alexander; Coren, Joshua

2012-10-01

Social networking Web sites such as Facebook have grown rapidly in popularity. It is unknown how such sites affect the ways in which medical trainees investigate and interact with graduate medical education (GME) programs. To evaluate the use of social networking Web sites as a means for osteopathic medical students, interns, residents, and fellows to interact with GME programs and report the degree to which that interaction impacts a medical trainee's choice of GME program. An anonymous, 10-item electronic survey on social networking Web sites was e-mailed to osteopathic medical student, intern, resident, and fellow members of the American College of Osteopathic Family Physicians. The weighted least squares test and the Fisher exact test were used for data analysis. A total of 9606 surveys were distributed, and 992 (10%) were completed. Nine hundred twenty-eight (93%) of the respondents used social networking Web sites, with the most popular services being Facebook (891 [90%]; P=.03), the Student Doctor Network (278 [28%]), and LinkedIn (89 [9%]; P=.03). Three hundred fifty-three respondents (36%; P=.52) were connected with a professional organization and 673 (68%; P=.73) used social networking Web sites for job searching related to GME programs or postresidency employment. Within the population of 497 third-, fourth-, and fifth-year osteopathic medical students, 136 (27%) reported gleaning information about programs through social networking Web sites (P=.01). Within the total population, 100 of 992 (10%) reported that this information influenced their decisions (P=.07). Of note, 144 (14%) of the total 992 respondents reported that the programs they applied to did not have any presence on social networking Web sites (P=.05). Our results indicate that social networking Web sites have a present and growing influence on how osteopathic medical students, interns, residents, and fellows learn about and select a GME program.

Racial/Ethnic Differences in Sexual Network Mixing: A Log-Linear Analysis of HIV Status by Partnership and Sexual Behavior Among Most at-Risk MSM.

PubMed

Fujimoto, Kayo; Williams, Mark L

2015-06-01

Mixing patterns within sexual networks have been shown to have an effect on HIV transmission, both within and across groups. This study examined sexual mixing patterns involving HIV-unknown status and risky sexual behavior conditioned on assortative/dissortative mixing by race/ethnicity. The sample used for this study consisted of drug-using male sex workers and their male sex partners. A log-linear analysis of 257 most at-risk MSM and 3,072 sex partners was conducted. The analysis found two significant patterns. HIV-positive most at-risk Black MSM had a strong tendency to have HIV-unknown Black partners (relative risk, RR = 2.91, p < 0.001) and to engage in risky sexual behavior (RR = 2.22, p < 0.001). White most at-risk MSM with unknown HIV status also had a tendency to engage in risky sexual behavior with Whites (RR = 1.72, p < 0.001). The results suggest that interventions that target the most at-risk MSM and their sex partners should account for specific sexual network mixing patterns by HIV status.

Noninvasive Visualization and Analysis of the Human Parafoveal Capillary Network Using Swept Source OCT Optical Microangiography.

PubMed

Kuehlewein, Laura; Tepelus, Tudor C; An, Lin; Durbin, Mary K; Srinivas, Sowmya; Sadda, Srinivas R

2015-06-01

We characterized the foveal avascular zone (FAZ) and the parafoveal capillary network in healthy subjects using swept source OCT optical microangiography (OMAG). We acquired OMAG images of the macula of 19 eyes (13 healthy individuals) using a prototype swept source laser OCT. En face images of the retinal vasculature were generated for superficial and deep inner retinal layers (SRL/DRL) in regions of interest 250 (ROI-250) and 500 (ROI-500) μm from the FAZ border. The mean area (mm2) of the FAZ was 0.304 ± 0.132 for the SRL and 0.486 ± 0.162 for the DRL (P < 0.001). Mean vessel density (%) was 67.3 ± 6.4 for the SRL and 34.5 ± 8.6 for the DRL in the ROI-250 (P < 0.001), and 74.2 ± 3.9 for the SRL and 72.3 ± 4.9 for the DRL in the ROI-500 (P = 0.160). Swept source OMAG images of healthy subjects allowed analysis of the FAZ and the density of the parafoveal capillary network at different retinal layers.

Spike-timing-dependent plasticity enhanced synchronization transitions induced by autapses in adaptive Newman-Watts neuronal networks.

PubMed

Gong, Yubing; Wang, Baoying; Xie, Huijuan

2016-12-01

In this paper, we numerically study the effect of spike-timing-dependent plasticity (STDP) on synchronization transitions induced by autaptic activity in adaptive Newman-Watts Hodgkin-Huxley neuron networks. It is found that synchronization transitions induced by autaptic delay vary with the adjusting rate A p of STDP and become strongest at a certain A p value, and the A p value increases when network randomness or network size increases. It is also found that the synchronization transitions induced by autaptic delay become strongest at a certain network randomness and network size, and the values increase and related synchronization transitions are enhanced when A p increases. These results show that there is optimal STDP that can enhance the synchronization transitions induced by autaptic delay in the adaptive neuronal networks. These findings provide a new insight into the roles of STDP and autapses for the information transmission in neural systems. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Assessing needs and assets for building a regional network infrastructure to reduce cancer related health disparities.

PubMed

Wells, Kristen J; Lima, Diana S; Meade, Cathy D; Muñoz-Antonia, Teresita; Scarinci, Isabel; McGuire, Allison; Gwede, Clement K; Pledger, W Jack; Partridge, Edward; Lipscomb, Joseph; Matthews, Roland; Matta, Jaime; Flores, Idhaliz; Weiner, Roy; Turner, Timothy; Miele, Lucio; Wiese, Thomas E; Fouad, Mona; Moreno, Carlos S; Lacey, Michelle; Christie, Debra W; Price-Haywood, Eboni G; Quinn, Gwendolyn P; Coppola, Domenico; Sodeke, Stephen O; Green, B Lee; Lichtveld, Maureen Y

2014-06-01

Significant cancer health disparities exist in the United States and Puerto Rico. While numerous initiatives have been implemented to reduce cancer disparities, regional coordination of these efforts between institutions is often limited. To address cancer health disparities nation-wide, a series of regional transdisciplinary networks through the Geographic Management Program (GMaP) and the Minority Biospecimen/Biobanking Geographic Management Program (BMaP) were established in six regions across the country. This paper describes the development of the Region 3 GMaP/BMaP network composed of over 100 investigators from nine institutions in five Southeastern states and Puerto Rico to develop a state-of-the-art network for cancer health disparities research and training. We describe a series of partnership activities that led to the formation of the infrastructure for this network, recount the participatory processes utilized to develop and implement a needs and assets assessment and implementation plan, and describe our approach to data collection. Completion, by all nine institutions, of the needs and assets assessment resulted in several beneficial outcomes for Region 3 GMaP/BMaP. This network entails ongoing commitment from the institutions and institutional leaders, continuous participatory and engagement activities, and effective coordination and communication centered on team science goals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing Needs and Assets for Building a Regional Network Infrastructure to Reduce Cancer Related Health Disparities

PubMed Central

Wells, Kristen J.; Lima, Diana S.; Meade, Cathy D.; Muñoz-Antonia, Teresita; Scarinci, Isabel; McGuire, Allison; Gwede, Clement K.; Pledger, W. Jack; Partridge, Edward; Lipscomb, Joseph; Matthews, Roland; Matta, Jaime; Flores, Idhaliz; Weiner, Roy; Turner, Timothy; Miele, Lucio; Wiese, Thomas E.; Fouad, Mona; Moreno, Carlos S.; Lacey, Michelle; Christie, Debra W.; Price-Haywood, Eboni G.; Quinn, Gwendolyn P.; Coppola, Domenico; Sodeke, Stephen O.; Green, B. Lee; Lichtveld, Maureen Y.

2015-01-01

Significant cancer health disparities exist in the United States and Puerto Rico. While numerous initiatives have been implemented to reduce cancer disparities, regional coordination of these efforts between institutions is often limited. To address cancer health disparities nationwide, a series of regional transdisciplinary networks through the Geographic Management Program (GMaP) and the Minority Biospecimen/Biobanking Geographic Management Program (BMaP) were established in six regions across the country. This paper describes the development of the Region 3 GMaP/BMaP network composed of over 100 investigators from nine institutions in five Southeastern states and Puerto Rico to develop a state-of-the-art network for cancer health disparities research and training. We describe a series of partnership activities that led to the formation of the infrastructure for this network, recount the participatory processes utilized to develop and implement a needs and assets assessment and implementation plan, and describe our approach to data collection. Completion, by all nine institutions, of the needs and assets assessment resulted in several beneficial outcomes for Region 3 GMaP/BMaP. This network entails ongoing commitment from the institutions and institutional leaders, continuous participatory and engagement activities, and effective coordination and communication centered on team science goals. PMID:24486917

Unstructured mesh adaptivity for urban flooding modelling

NASA Astrophysics Data System (ADS)

Hu, R.; Fang, F.; Salinas, P.; Pain, C. C.

2018-05-01

Over the past few decades, urban floods have been gaining more attention due to their increase in frequency. To provide reliable flooding predictions in urban areas, various numerical models have been developed to perform high-resolution flood simulations. However, the use of high-resolution meshes across the whole computational domain causes a high computational burden. In this paper, a 2D control-volume and finite-element flood model using adaptive unstructured mesh technology has been developed. This adaptive unstructured mesh technique enables meshes to be adapted optimally in time and space in response to the evolving flow features, thus providing sufficient mesh resolution where and when it is required. It has the advantage of capturing the details of local flows and wetting and drying front while reducing the computational cost. Complex topographic features are represented accurately during the flooding process. For example, the high-resolution meshes around the buildings and steep regions are placed when the flooding water reaches these regions. In this work a flooding event that happened in 2002 in Glasgow, Scotland, United Kingdom has been simulated to demonstrate the capability of the adaptive unstructured mesh flooding model. The simulations have been performed using both fixed and adaptive unstructured meshes, and then results have been compared with those published 2D and 3D results. The presented method shows that the 2D adaptive mesh model provides accurate results while having a low computational cost.

Quantum Inference on Bayesian Networks

NASA Astrophysics Data System (ADS)

Yoder, Theodore; Low, Guang Hao; Chuang, Isaac

2014-03-01

Because quantum physics is naturally probabilistic, it seems reasonable to expect physical systems to describe probabilities and their evolution in a natural fashion. Here, we use quantum computation to speedup sampling from a graphical probability model, the Bayesian network. A specialization of this sampling problem is approximate Bayesian inference, where the distribution on query variables is sampled given the values e of evidence variables. Inference is a key part of modern machine learning and artificial intelligence tasks, but is known to be NP-hard. Classically, a single unbiased sample is obtained from a Bayesian network on n variables with at most m parents per node in time (nmP(e) - 1 / 2) , depending critically on P(e) , the probability the evidence might occur in the first place. However, by implementing a quantum version of rejection sampling, we obtain a square-root speedup, taking (n2m P(e) -1/2) time per sample. The speedup is the result of amplitude amplification, which is proving to be broadly applicable in sampling and machine learning tasks. In particular, we provide an explicit and efficient circuit construction that implements the algorithm without the need for oracle access.

Structural characterization of 2,6-dichloro-p-hydroquinone 1,2-dioxygenase (PcpA) from Sphingobium chlorophenolicum, a new type of aromatic ring-cleavage enzyme.

PubMed

Hayes, Robert P; Green, Abigail R; Nissen, Mark S; Lewis, Kevin M; Xun, Luying; Kang, Chulhee

2013-05-01

PcpA (2,6-dichloro-p-hydroquinone 1,2-dioxygenase) from Sphingobium chlorophenolicum, a non-haem Fe(II) dioxygenase capable of cleaving the aromatic ring of p-hydroquinone and its substituted variants, is a member of the recently discovered p-hydroquinone 1,2-dioxygenases. Here we report the 2.6 Å structure of PcpA, which consists of four βαβββ motifs, a hallmark of the vicinal oxygen chelate superfamily. The secondary co-ordination sphere of the Fe(II) centre forms an extensive hydrogen-bonding network with three solvent exposed residues, linking the catalytic Fe(II) to solvent. A tight hydrophobic pocket provides p-hydroquinones access to the Fe(II) centre. The p-hydroxyl group is essential for the substrate-binding, thus phenols and catechols, lacking a p-hydroxyl group, do not bind to PcpA. Site-directed mutagenesis and kinetic analysis confirm the critical catalytic role played by the highly conserved His10, Thr13, His226 and Arg259. Based on these results, we propose a general reaction mechanism for p-hydroquinone 1,2-dioxygenases. © 2013 Blackwell Publishing Ltd.

Structural characterization of 2,6-dichloro-p-hydroquinone 1,2-dioxygenase (PcpA) from Sphingobium chlorophenolicum, a new type of aromatic ring-cleavage enzyme

PubMed Central

Hayes, Robert P.; Green, Abigail R.; Nissen, Mark S.; Lewis, Kevin M.; Xun, Luying; Kang, ChulHee

2014-01-01

Summary PcpA (2,6-dichloro-p-hydroquinone 1,2-dioxygenase) from Sphingobium chlorophenolicum, a non-haem Fe(II) dioxygenase capable of cleaving the aromatic ring of p-hydroquinone and its substituted variants, is a member of the recently discovered p-hydroquinone 1,2-dioxygenases. Here we report the 2.6 Å structure of PcpA, which consists of four βαβββ motifs, a hallmark of the vicinal oxygen chelate superfamily. The secondary co-ordination sphere of the Fe(II) centre forms an extensive hydrogen-bonding network with three solvent exposed residues, linking the catalytic Fe(II) to solvent. A tight hydrophobic pocket provides p-hydroquinones access to the Fe(II) centre. The p-hydroxyl group is essential for the substrate-binding, thus phenols and catechols, lacking a p-hydroxyl group, do not bind to PcpA. Site-directed mutagenesis and kinetic analysis confirm the critical catalytic role played by the highly conserved His10, Thr13, His226 and Arg259. Based on these results, we propose a general reaction mechanism for p-hydroquinone 1,2-dioxygenases. PMID:23489289

pH responsive N-succinyl chitosan/Poly (acrylamide-co-acrylic acid) hydrogels and in vitro release of 5-fluorouracil.

PubMed

Bashir, Shahid; Teo, Yin Yin; Naeem, Sumaira; Ramesh, S; Ramesh, K

2017-01-01

There has been significant progress in the last few decades in addressing the biomedical applications of polymer hydrogels. Particularly, stimuli responsive hydrogels have been inspected as elegant drug delivery systems capable to deliver at the appropriate site of action within the specific time. The present work describes the synthesis of pH responsive semi-interpenetrating network (semi-IPN) hydrogels of N-succinyl-chitosan (NSC) via Schiff base mechanism using glutaraldehyde as a crosslinking agent and Poly (acrylamide-co-acrylic acid)(Poly (AAm-co-AA)) was embedded within the N-succinyl chitosan network. The physico-chemical interactions were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM). The synthesized hydrogels constitute porous structure. The swelling ability was analyzed in physiological mediums of pH 7.4 and pH 1.2 at 37°C. Swelling properties of formulations with various amounts of NSC/ Poly (AAm-co-AA) and crosslinking agent at pH 7.4 and pH 1.2 were investigated. Hydrogels showed higher swelling ratios at pH 7.4 while lower at pH 1.2. Swelling kinetics and diffusion parameters were also determined. Drug loading, encapsulation efficiency, and in vitro release of 5-fluorouracil (5-FU) from the synthesized hydrogels were observed. In vitro release profile revealed the significant influence of pH, amount of NSC, Poly (AAm-co-AA), and crosslinking agent on the release of 5-FU. Accordingly, rapid and large release of drug was observed at pH 7.4 than at pH 1.2. The maximum encapsulation efficiency and release of 5-FU from SP2 were found to be 72.45% and 85.99%, respectively. Kinetics of drug release suggested controlled release mechanism of 5-FU is according to trend of non-Fickian. From the above results, it can be concluded that the synthesized hydrogels have capability to adapt their potential exploitation as targeted oral drug delivery carriers.

pH responsive N-succinyl chitosan/Poly (acrylamide-co-acrylic acid) hydrogels and in vitro release of 5-fluorouracil

PubMed Central

Bashir, Shahid; Teo, Yin Yin; Naeem, Sumaira; Ramesh, S.; Ramesh, K.

2017-01-01

There has been significant progress in the last few decades in addressing the biomedical applications of polymer hydrogels. Particularly, stimuli responsive hydrogels have been inspected as elegant drug delivery systems capable to deliver at the appropriate site of action within the specific time. The present work describes the synthesis of pH responsive semi-interpenetrating network (semi-IPN) hydrogels of N-succinyl-chitosan (NSC) via Schiff base mechanism using glutaraldehyde as a crosslinking agent and Poly (acrylamide-co-acrylic acid)(Poly (AAm-co-AA)) was embedded within the N-succinyl chitosan network. The physico-chemical interactions were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM). The synthesized hydrogels constitute porous structure. The swelling ability was analyzed in physiological mediums of pH 7.4 and pH 1.2 at 37°C. Swelling properties of formulations with various amounts of NSC/ Poly (AAm-co-AA) and crosslinking agent at pH 7.4 and pH 1.2 were investigated. Hydrogels showed higher swelling ratios at pH 7.4 while lower at pH 1.2. Swelling kinetics and diffusion parameters were also determined. Drug loading, encapsulation efficiency, and in vitro release of 5-fluorouracil (5-FU) from the synthesized hydrogels were observed. In vitro release profile revealed the significant influence of pH, amount of NSC, Poly (AAm-co-AA), and crosslinking agent on the release of 5-FU. Accordingly, rapid and large release of drug was observed at pH 7.4 than at pH 1.2. The maximum encapsulation efficiency and release of 5-FU from SP2 were found to be 72.45% and 85.99%, respectively. Kinetics of drug release suggested controlled release mechanism of 5-FU is according to trend of non-Fickian. From the above results, it can be concluded that the synthesized hydrogels have capability to adapt their potential exploitation as targeted oral drug delivery carriers. PMID:28678803

Increases in New Social Network Ties are Associated with Increased Cohesion among Intervention Participants

PubMed Central

Gesell, Sabina B.; Barkin, Shari L.; Sommer, Evan C.; Thompson, Jessica R.; Valente, Thomas W.

2016-01-01

Objective Many behavior change programs are delivered in group settings to manage implementation costs and to foster support and interactions among group members to facilitate behavior change. Understanding the group dynamics that evolve in group settings (e.g., weight management, Alcoholics Anonymous) is important, yet rarely measured. This paper examined the relationship between social network ties and group cohesion in a group-based intervention to prevent obesity in children. Method The data reported are process measures from an ongoing community-based randomized controlled trial. 305 parents with a child (3-6 years) at risk of developing obesity were assigned to an intervention that taught parents healthy lifestyles. Parents met weekly for 12 weeks in small consistent groups. Two measures were collected at weeks 3 and 6: a social network survey (people in the group with whom one discusses healthy lifestyles); and the validated Perceived Cohesion Scale (Bollen & Hoyle, 1990). We used lagged random and fixed effects regression models to analyze the data. Results Cohesion increased from 6.51 to 6.71 (t=4.4, p<0.01). Network nominations tended to increase over the 3-week period in each network. In the combined discussion and advice network, the number of nominations increased from 1.76 to 1.95 (z=2.59, p<0.01). Cohesion at week 3 was the strongest predictor of cohesion at week 6 (b=0.55, p<0.01). Number of new network nominations at week 6 was positively related to cohesion at week 6 (b=0.06, p<.01). In sum, being able to name new network contacts was associated with feelings of cohesion. Conclusion This is the first study to demonstrate how network changes affect perceived group cohesion within a behavioral intervention. Given that many behavioral interventions occur in group settings, intentionally building new social networks could be promising to augment desired outcomes. PMID:26286298

Increases in Network Ties Are Associated With Increased Cohesion Among Intervention Participants.

PubMed

Gesell, Sabina B; Barkin, Shari L; Sommer, Evan C; Thompson, Jessica R; Valente, Thomas W

2016-04-01

Many behavior change programs are delivered in group settings to manage implementation costs and to foster support and interactions among group members in order to facilitate behavior change. Understanding the group dynamics that evolve in group settings (e.g., weight management, Alcoholics Anonymous) is important, yet rarely measured. This article examined the relationship between social network ties and group cohesion in a group-based intervention to prevent obesity in children. The data reported are process measures from an ongoing community-based randomized controlled trial. A total of 305 parents with a child (3-6 years) at risk of developing obesity were assigned to an intervention that taught parents healthy lifestyles. Parents met weekly for 12 weeks in small consistent groups. Two measures were collected at Weeks 3 and 6: a social network survey (people in the group with whom one discusses healthy lifestyles) and the validated Perceived Cohesion Scale. We used lagged random and fixed effects regression models to analyze the data. Cohesion increased from 6.51 to 6.71 (t= 4.4,p< .01). Network nominations tended to increase over the 3-week period in each network. In the combined discussion and advice network, the number of nominations increased from 1.76 to 1.95 (z= 2.59,p< .01). Cohesion at Week 3 was the strongest predictor of cohesion at Week 6 (b= 0.55,p< .01). Number of new network nominations at Week 6 was positively related to cohesion at Week 6 (b= 0.06,p< .01). In sum, being able to name new network contacts was associated with feelings of cohesion. This is the first study to demonstrate how network changes affect perceived group cohesion within a behavioral intervention. Given that many behavioral interventions occur in group settings, intentionally building new social networks could be promising to augment desired outcomes. © 2015 Society for Public Health Education.

77 FR 74674 - National Center for Advancing Translational Sciences; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-17

... Network Review Board. The meeting will be open to the public, with attendance limited to space available... Committee: Cures Acceleration Network Review Board. Date: January 23, 2013. Time: 8:30 a.m. to 2:45 p.m...

Cross Cancer Genomic Investigation of Inflammation Pathway for Five Common Cancers: Lung, Ovary, Prostate, Breast, and Colorectal Cancer

PubMed Central

Ulrich, Cornelia M.; Goode, Ellen L.; Brhane, Yonathan; Muir, Kenneth; Chan, Andrew T.; Marchand, Loic Le; Schildkraut, Joellen; Witte, John S.; Eeles, Rosalind; Boffetta, Paolo; Spitz, Margaret R.; Poirier, Julia G.; Rider, David N.; Fridley, Brooke L.; Chen, Zhihua; Haiman, Christopher; Schumacher, Fredrick; Easton, Douglas F.; Landi, Maria Teresa; Brennan, Paul; Houlston, Richard; Christiani, David C.; Field, John K.; Bickeböller, Heike; Risch, Angela; Kote-Jarai, Zsofia; Wiklund, Fredrik; Grönberg, Henrik; Chanock, Stephen; Berndt, Sonja I.; Kraft, Peter; Lindström, Sara; Al Olama, Ali Amin; Song, Honglin; Phelan, Catherine; Wentzensen, Nicholas; Peters, Ulrike; Slattery, Martha L.; Sellers, Thomas A.; Casey, Graham; Gruber, Stephen B.; Hunter, David J.; Amos, Christopher I.; Henderson, Brian

2015-01-01

Background: Inflammation has been hypothesized to increase the risk of cancer development as an initiator or promoter, yet no large-scale study of inherited variation across cancer sites has been conducted. Methods: We conducted a cross-cancer genomic analysis for the inflammation pathway based on 48 genome-wide association studies within the National Cancer Institute GAME-ON Network across five common cancer sites, with a total of 64 591 cancer patients and 74 467 control patients. Subset-based meta-analysis was used to account for possible disease heterogeneity, and hierarchical modeling was employed to estimate the effect of the subcomponents within the inflammation pathway. The network was visualized by enrichment map. All statistical tests were two-sided. Results: We identified three pleiotropic loci within the inflammation pathway, including one novel locus in Ch12q24 encoding SH2B3 (rs3184504), which reached GWAS significance with a P value of 1.78 x 10–8, and it showed an association with lung cancer (P = 2.01 x 10–6), colorectal cancer (GECCO P = 6.72x10-6; CORECT P = 3.32x10-5), and breast cancer (P = .009). We also identified five key subpathway components with genetic variants that are relevant for the risk of these five cancer sites: inflammatory response for colorectal cancer (P = .006), inflammation related cell cycle gene for lung cancer (P = 1.35x10-6), and activation of immune response for ovarian cancer (P = .009). In addition, sequence variations in immune system development played a role in breast cancer etiology (P = .001) and innate immune response was involved in the risk of both colorectal (P = .022) and ovarian cancer (P = .003). Conclusions: Genetic variations in inflammation and its related subpathway components are keys to the development of lung, colorectal, ovary, and breast cancer, including SH2B3, which is associated with lung, colorectal, and breast cancer. PMID:26319099

Structure-topology-property correlations of sodium phosphosilicate glasses.

PubMed

Hermansen, Christian; Guo, Xiaoju; Youngman, Randall E; Mauro, John C; Smedskjaer, Morten M; Yue, Yuanzheng

2015-08-14

In this work, we investigate the correlations among structure, topology, and properties in a series of sodium phosphosilicate glasses with [SiO2]/[SiO2 + P2O5] ranging from 0 to 1. The network structure is characterized by (29)Si and (31)P magic-angle spinning nuclear magnetic resonance and Raman spectroscopy. The results show the formation of six-fold coordinated silicon species in phosphorous-rich glasses. Based on the structural data, we propose a formation mechanism of the six-fold coordinated silicon, which is used to develop a quantitative structural model for predicting the speciation of the network forming units as a function of chemical composition. The structural model is then used to establish a temperature-dependent constraint description of phosphosilicate glass topology that enables prediction of glass transition temperature, liquid fragility, and indentation hardness. The topological constraint model provides insight into structural origin of the mixed network former effect in phosphosilicate glasses.

A measurement of t$$\\bar{t}$$ production cross section in p$$\\bar{p}$$ collisions at √s = 1.8 TeV using neural networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Harpreet

The authors present the results of a new measurement of the tmore » $$\\bar{t}$$ production cross section using eμ channel in p$$\\bar{p}$$ collisions at √s = 1.8 TeV. This study corresponds to an integrated luminosity of 108.3 ± 5.7 pb -1 acquired by the D0 detector during the Fermilab Tevatron Collider Run 1 (1992--1996). By using neural network techniques instead of the conventional analysis methods, the authors show that the signal acceptance can be increased by 10% (for m t = 172 GeV/c 2) while the background remains constant. Four eμ events are observed in data with an estimated background of 0.22 ± 0.14 corresponding to a t$$\\bar{t}$$ production cross section of 9.75 ± 5.53 pb.« less

Artificial intelligence in healthcare: past, present and future.

PubMed

Jiang, Fei; Jiang, Yong; Zhi, Hui; Dong, Yi; Li, Hao; Ma, Sufeng; Wang, Yilong; Dong, Qiang; Shen, Haipeng; Wang, Yongjun

2017-12-01

Artificial intelligence (AI) aims to mimic human cognitive functions. It is bringing a paradigm shift to healthcare, powered by increasing availability of healthcare data and rapid progress of analytics techniques. We survey the current status of AI applications in healthcare and discuss its future. AI can be applied to various types of healthcare data (structured and unstructured). Popular AI techniques include machine learning methods for structured data, such as the classical support vector machine and neural network, and the modern deep learning, as well as natural language processing for unstructured data. Major disease areas that use AI tools include cancer, neurology and cardiology. We then review in more details the AI applications in stroke, in the three major areas of early detection and diagnosis, treatment, as well as outcome prediction and prognosis evaluation. We conclude with discussion about pioneer AI systems, such as IBM Watson, and hurdles for real-life deployment of AI.

Artificial intelligence in healthcare: past, present and future

PubMed Central

Jiang, Fei; Jiang, Yong; Zhi, Hui; Dong, Yi; Li, Hao; Ma, Sufeng; Wang, Yilong; Dong, Qiang; Shen, Haipeng; Wang, Yongjun

2017-01-01

Artificial intelligence (AI) aims to mimic human cognitive functions. It is bringing a paradigm shift to healthcare, powered by increasing availability of healthcare data and rapid progress of analytics techniques. We survey the current status of AI applications in healthcare and discuss its future. AI can be applied to various types of healthcare data (structured and unstructured). Popular AI techniques include machine learning methods for structured data, such as the classical support vector machine and neural network, and the modern deep learning, as well as natural language processing for unstructured data. Major disease areas that use AI tools include cancer, neurology and cardiology. We then review in more details the AI applications in stroke, in the three major areas of early detection and diagnosis, treatment, as well as outcome prediction and prognosis evaluation. We conclude with discussion about pioneer AI systems, such as IBM Watson, and hurdles for real-life deployment of AI. PMID:29507784

Application of an unstructured grid flow solver to planes, trains and automobiles

NASA Technical Reports Server (NTRS)

Spragle, Gregory S.; Smith, Wayne A.; Yadlin, Yoram

1993-01-01

Rampant, an unstructured flow solver developed at Fluent Inc., is used to compute three-dimensional, viscous, turbulent, compressible flow fields within complex solution domains. Rampant is an explicit, finite-volume flow solver capable of computing flow fields using either triangular (2d) or tetrahedral (3d) unstructured grids. Local time stepping, implicit residual smoothing, and multigrid techniques are used to accelerate the convergence of the explicit scheme. The paper describes the Rampant flow solver and presents flow field solutions about a plane, train, and automobile.

Gallium incorporation into phosphate based glasses: Bulk and thin film properties.

PubMed

Stuart, Bryan W; Grant, Colin A; Stan, George E; Popa, Adrian C; Titman, Jeremy J; Grant, David M

2018-06-01

The osteogenic ions Ca 2+ , P 5+ , Mg 2+ , and antimicrobial ion Ga 3+ were homogenously dispersed into a 1.45 µm thick phosphate glass coating by plasma assisted sputtering onto commercially pure grade titanium. The objective was to deliver therapeutic ions in orthopaedic/dental implants such as cementeless endoprostheses or dental screws. The hardness 4.7 GPa and elastic modulus 69.7 GPa, of the coating were comparable to plasma sprayed hydroxyapatite/dental enamel, whilst superseding femoral cortical bone. To investigate the manufacturing challenge of translation from a target to vapour condensed coating, structural/compositional properties of the target (P51MQ) were compared to the coating (P40PVD) and a melt-quenched equivalent (P40MQ). Following condensation from P51MQ to P40PVD, P 2 O 5 content reduced from 48.9 to 40.5 mol%. This depolymerisation and reduction in the P-O-P bridging oxygen content as determined by 31 P NMR, FTIR and Raman spectroscopy techniques was attributed to a decrease in the P 2 O 5 network former and increases in alkali/alkali-earth cations. P40PVD appeared denser (3.47 vs. 2.70 g cm -3 ) and more polymerised than it's compositionally equivalent P40MQ, showing that structure/ mechanical properties were affected by manufacturing route. Copyright © 2018. Published by Elsevier Ltd.

Comparative Reliability of Structured Versus Unstructured Interviews in the Admission Process of a Residency Program

PubMed Central

Blouin, Danielle; Day, Andrew G.; Pavlov, Andrey

2011-01-01

Background Although never directly compared, structured interviews are reported as being more reliable than unstructured interviews. This study compared the reliability of both types of interview when applied to a common pool of applicants for positions in an emergency medicine residency program. Methods In 2008, one structured interview was added to the two unstructured interviews traditionally used in our resident selection process. A formal job analysis using the critical incident technique guided the development of the structured interview tool. This tool consisted of 7 scenarios assessing 4 of the domains deemed essential for success as a resident in this program. The traditional interview tool assessed 5 general criteria. In addition to these criteria, the unstructured panel members were asked to rate each candidate on the same 4 essential domains rated by the structured panel members. All 3 panels interviewed all candidates. Main outcomes were the overall, interitem, and interrater reliabilities, the correlations between interview panels, and the dimensionality of each interview tool. Results Thirty candidates were interviewed. The overall reliability reached 0.43 for the structured interview, and 0.81 and 0.71 for the unstructured interviews. Analyses of the variance components showed a high interrater, low interitem reliability for the structured interview, and a high interrater, high interitem reliability for the unstructured interviews. The summary measures from the 2 unstructured interviews were significantly correlated, but neither was correlated with the structured interview. Only the structured interview was multidimensional. Conclusions A structured interview did not yield a higher overall reliability than both unstructured interviews. The lower reliability is explained by a lower interitem reliability, which in turn is due to the multidimensionality of the interview tool. Both unstructured panels consistently rated a single dimension, even when prompted to assess the 4 specific domains established as essential to succeed in this residency program. PMID:23205201

Comparative reliability of structured versus unstructured interviews in the admission process of a residency program.

PubMed

Blouin, Danielle; Day, Andrew G; Pavlov, Andrey

2011-12-01

Although never directly compared, structured interviews are reported as being more reliable than unstructured interviews. This study compared the reliability of both types of interview when applied to a common pool of applicants for positions in an emergency medicine residency program. In 2008, one structured interview was added to the two unstructured interviews traditionally used in our resident selection process. A formal job analysis using the critical incident technique guided the development of the structured interview tool. This tool consisted of 7 scenarios assessing 4 of the domains deemed essential for success as a resident in this program. The traditional interview tool assessed 5 general criteria. In addition to these criteria, the unstructured panel members were asked to rate each candidate on the same 4 essential domains rated by the structured panel members. All 3 panels interviewed all candidates. Main outcomes were the overall, interitem, and interrater reliabilities, the correlations between interview panels, and the dimensionality of each interview tool. Thirty candidates were interviewed. The overall reliability reached 0.43 for the structured interview, and 0.81 and 0.71 for the unstructured interviews. Analyses of the variance components showed a high interrater, low interitem reliability for the structured interview, and a high interrater, high interitem reliability for the unstructured interviews. The summary measures from the 2 unstructured interviews were significantly correlated, but neither was correlated with the structured interview. Only the structured interview was multidimensional. A structured interview did not yield a higher overall reliability than both unstructured interviews. The lower reliability is explained by a lower interitem reliability, which in turn is due to the multidimensionality of the interview tool. Both unstructured panels consistently rated a single dimension, even when prompted to assess the 4 specific domains established as essential to succeed in this residency program.

Parallel Performance Optimizations on Unstructured Mesh-based Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarje, Abhinav; Song, Sukhyun; Jacobsen, Douglas

2015-01-01

© The Authors. Published by Elsevier B.V. This paper addresses two key parallelization challenges the unstructured mesh-based ocean modeling code, MPAS-Ocean, which uses a mesh based on Voronoi tessellations: (1) load imbalance across processes, and (2) unstructured data access patterns, that inhibit intra- and inter-node performance. Our work analyzes the load imbalance due to naive partitioning of the mesh, and develops methods to generate mesh partitioning with better load balance and reduced communication. Furthermore, we present methods that minimize both inter- and intranode data movement and maximize data reuse. Our techniques include predictive ordering of data elements for higher cachemore » efficiency, as well as communication reduction approaches. We present detailed performance data when running on thousands of cores using the Cray XC30 supercomputer and show that our optimization strategies can exceed the original performance by over 2×. Additionally, many of these solutions can be broadly applied to a wide variety of unstructured grid-based computations.« less

Yeast ribonuclease III uses a network of multiple hydrogen bonds for RNA binding and cleavage.

PubMed

Lavoie, Mathieu; Abou Elela, Sherif

2008-08-19

Members of the bacterial RNase III family recognize a variety of short structured RNAs with few common features. It is not clear how this group of enzymes supports high cleavage fidelity while maintaining a broad base of substrates. Here we show that the yeast orthologue of RNase III (Rnt1p) uses a network of 2'-OH-dependent interactions to recognize substrates with different structures. We designed a series of bipartite substrates permitting the distinction between binding and cleavage defects. Each substrate was engineered to carry a single or multiple 2'- O-methyl or 2'-fluoro ribonucleotide substitutions to prevent the formation of hydrogen bonds with a specific nucleotide or group of nucleotides. Interestingly, introduction of 2'- O-methyl ribonucleotides near the cleavage site increased the rate of catalysis, indicating that 2'-OH are not required for cleavage. Substitution of nucleotides in known Rnt1p binding site with 2'- O-methyl ribonucleotides inhibited cleavage while single 2'-fluoro ribonucleotide substitutions did not. This indicates that while no single 2'-OH is essential for Rnt1p cleavage, small changes in the substrate structure are not tolerated. Strikingly, several nucleotide substitutions greatly increased the substrate dissociation constant with little or no effect on the Michaelis-Menten constant or rate of catalysis. Together, the results indicate that Rnt1p uses a network of nucleotide interactions to identify its substrate and support two distinct modes of binding. One mode is primarily mediated by the dsRNA binding domain and leads to the formation of stable RNA/protein complex, while the other requires the presence of the nuclease and N-terminal domains and leads to RNA cleavage.

Interactions of Histone Acetyltransferase p300 with the Nuclear Proteins Histone and HMGB1, As Revealed by Single Molecule Atomic Force Spectroscopy.

PubMed

Banerjee, S; Rakshit, T; Sett, S; Mukhopadhyay, R

2015-10-22

One of the important properties of the transcriptional coactivator p300 is histone acetyltransferase (HAT) activity that enables p300 to influence chromatin action via histone modulation. p300 can exert its HAT action upon the other nuclear proteins too--one notable example being the transcription-factor-like protein HMGB1, which functions also as a cytokine, and whose accumulation in the cytoplasm, as a response to tissue damage, is triggered by its acetylation. Hitherto, no information on the structure and stability of the complexes between full-length p300 (p300FL) (300 kDa) and the histone/HMGB1 proteins are available, probably due to the presence of unstructured regions within p300FL that makes it difficult to be crystallized. Herein, we have adopted the high-resolution atomic force microscopy (AFM) approach, which allows molecularly resolved three-dimensional contour mapping of a protein molecule of any size and structure. From the off-rate and activation barrier values, obtained using single molecule dynamic force spectroscopy, the biochemical proposition of preferential binding of p300FL to histone H3, compared to the octameric histone, can be validated. Importantly, from the energy landscape of the dissociation events, a model for the p300-histone and the p300-HMGB1 dynamic complexes that HAT forms, can be proposed. The lower unbinding forces of the complexes observed in acetylating conditions, compared to those observed in non-acetylating conditions, indicate that upon acetylation, p300 tends to weakly associate, probably as an outcome of charge alterations on the histone/HMGB1 surface and/or acetylation-induced conformational changes. To our knowledge, for the first time, a single molecule level treatment of the interactions of HAT, where the full-length protein is considered, is being reported.

Expression and function of the metabotropic purinergic P2Y receptor family in experimental seizure models and patients with drug-refractory epilepsy.

PubMed

Alves, Mariana; Gomez-Villafuertes, Rosa; Delanty, Norman; Farrell, Michael A; O'Brien, Donncha F; Miras-Portugal, Maria Teresa; Hernandez, Miguel Diaz; Henshall, David C; Engel, Tobias

2017-09-01

ATP is released into the extracellular space during pathologic processes including increased neuronal firing. Once released, ATP acts on P2 receptors including ionotropic P2X and metabotropic P2Y receptors, resulting in changes to glial function and neuronal network excitability. Evidence suggests an involvement of P2Y receptors in the pathogenesis of epilepsy, but there has been no systematic effort to characterize the expression and function of the P2Y receptor family during seizures and in experimental and human epilepsy. Status epilepticus was induced using either intra-amygdala kainic acid or pilocarpine to characterize the acute- and long-term changes in hippocampal P2Y expression. P2Y expression was also investigated in brain tissue from patients with temporal lobe epilepsy. Finally, we analyzed the effects of two specific P2Y agonists, ADP and UTP, on seizure severity and seizure-induced cell death. Both intra-amygdala kainic acid and pilocarpine-induced status epilepticus increased the transcription of the uracil-sensitive P2Y receptors P2ry 2 , P2ry 4 , and P2ry 6 and decreased the transcription of the adenine-sensitive P2Y receptors P2ry 1 , P2ry 12 , P2ry 13 . Protein levels of P2Y 1 , P2Y 2 , P2Y 4 , and P2Y 6 were increased after status epilepticus, whereas P2Y 12 expression was decreased. In the chronic phase, P2ry 1 , P2ry 2 , and P2ry 6 transcription and P2Y 1 , P2Y 2 , and P2Y 12 protein levels were increased with no changes for the other P2Y receptors. In hippocampal samples from patients with temporal lobe epilepsy, P2Y 1 and P2Y 2 protein expression was increased, whereas P2Y 13 levels were lower. Demonstrating a functional contribution of P2Y receptors to seizures, central injection of ADP exacerbated seizure severity, whereas treatment with UTP decreased seizure severity during status epilepticus in mice. The present study is the first to establish the specific hippocampal expression profile and function of the P2Y receptor family after experimental status epilepticus and in human temporal lobe epilepsy and offers potential new targets for seizure control and disease modification. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.